Lecture Notes on Human Anatomy. Part One, Fourth Edition. PUB DATE Sep 89 NOTE 79P.; for Related Documents, See SE 051 219-221

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AUTHOR Conrey, Kathleen TITLE Lecture Notes on Human Anatomy. Part One, Fourth Edition. PUB DATE Sep 89 NOTE 79p.; For related documents, see SE 051 219-221. Black and white illustrations will not reproduce clearly. AVAILABLE FROM Aramaki Design and Publications, 12077 Jefferson Blvd., Culver City, CA 90506 ($7.75). PUB TYPE Guides - Classroom Use - Materials (For Learner) (051)

EDRS PRICE MF01 Plus Postage. PC Not Available from EDRS. DESCRIPTORS *Anatomy; *Biological Sciences; *College Science; Higher Education; *Human Body; *Lecture Method; Science Education; Secondary Education; Secondary School Science; Teaching Guides; Teaching Methods

ABSTRACT During the process of studying the specific course content of human anatomy, students are being educated to expand their vocabulary, deal successfully with complex tasks, anduse a specific way of thinking. This is the first volume in a set of notes which are designed to accompany a lecture series in human anatomy. This volume Includes discussions of anatomical planes and positions, body cavities, and architecture; studies of the skeleton including bones and joints; studies of the musculature of the body; and studiesof the nervous system including the central, autonomic, motor and sensory systems. (CW)

*****1.**k07********Y*******t1.****+***********,****A*******r****** % Reproductions supplied by EDRS are the best that can be made from the original document. **************************************************************A**t***** "PERMISSION TO REPRODUCE THIS MATERIAL IN MICROFICHE ONLY AS BEEN GRANTE Y U.S. DEPARTMENT OF EDUCATION Ofhce ot Edircabonal Researchand Improvement 1\1een prey. EDUCATIONAL RESOURCES INFORMATION CENTFR (ER/0 XThre document Pies been reproduced as eCeneed from the person of organization onginating 4 TO THE EDUCATIONAL RESOURCES r' Minot changes have been made toimprove ere ,ducton ouabzy LECTURE INFORMATION CENTER (ERIC)." Points of weir Or opornOnti StatedIn thtsdocu ment do not neCeSSarily represent ottreial OERI position co poticy

Part Fourth Edition

by KATHLEEN CONREY

9 LECTURE NOTES on HUMAN ANATOMY

Part One Fourth Edition

The author is a Professor of Natural Sciencesat El Camino College. She holds a master's degree from the Department of I luman Anatomy, University ofCalifornia, San Francisco, and has been teaching human anatomy at the community college level since1967.

by KATHLEEN CONREY Aramaki Design & Publications 12077 Jefferson Boulevard, Culver City, California (213) 822-9800

Fourth Edition, September, 1989 Copyright @1988 by Kathleen Conrey

All rights reserved No part of this publicati9n may be reproduced, stored ina retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recordingor otherwise, without the prior written permission of the copyrightowner.

First edition and first printing 1982

Printed in the United States of America TABLE OF CONTENTS

PREFACE iii

INTRODUCTION 1

Anatomical Position 1 Planes 2 Body Cavities 3 Miscellaneous Terms 3 Body Architecture 3 BONE TERMINOLOGY 4 OSSIFICATION Special Terms 5 Intramembranous 5 Endochondral 5 Summary 7 ARTHROLOGY 9 Joint Classification 9 Parts of a Synovial Joint 9 Joint Movements 10 Other Synovial Sacs 10

SPECIFIC JOINT FEATURES 11 Shoulder Joint 11 Elbow Joint 11 Hip Joint 11 Sacral Joints 12 Patello-Femoral Joint 13 Knee Joint 13

GROSS ANATOMY OF MUSCLES 15 Origin and Insertion 15 Action 15

MUSCLES OF TIIE HEAD 16 Facial Expression 16 Mastication 17

MUSCLES OF THE NECK & DEEP TORSO 18 Strap Muscles 18 Suprahyoid Group 18 Infrahyoid Group 18 Posterior Triangle 18 Breathing Muscles 19 Posture Muscles 20 Deep Back & Neck 20

MUSCLES OF POSTERIOR ABDOMINAL WALL 21

Lecture Notes Part I i Table of Contents MUSCLES OF ANTERIOR ABDOMINAL WALL 22 Descent of Testes 24 UPPER LIMB Mooring Muscles 25 Shoulder Joint 27 Elbow Joint 30 Wrist and Finger Joints 32 LOWER LIMB Hip and Thigh 35 Lower Leg 39 NERVOUS SYSTEM INTRODUCTION Basic Terminology and Basic Concepts 43 SPINAL CORD ANATOMY & SPINAL NERVES 45 Spinal Reflex Arc 45 Spinal Cord Terminology 45 Spinal Nerves and Their Distribution 46 AUTONOMIC NERVOUS SYSTEM 48 CRANIAL NERVES 51 VENTRICLES, SPINAL FLUID, MENINGES, BLOOD SUPPLY 53 Ventricles 53 Cerebral Spinal Fluid 53 Meninges 54 Venous Drainage of the Brain 55 Blood Supply to Brain 55 Blood Brain Barrier 55 EMBRYOLOGY OF THE BRAIN 56 ADULT ANATOMY OF THE BRAIN 59 Rhombencephalon 59 Mesencephalon 59 Prosencephalon 60 MAJOR PATHWAYS 63 GENERAL SENSORY RECEPTORS 65 THE EYE 67 THE EAR 70

Lecture Notes Part I ii Table of Contents PREFACE

I have written this book to make your job as secondary processes as the "hidden a student easier. I am writing this preface in agenda" of a college education. Theyare hopes that I hidden, not can help you to because get beyond the Perhaps the most important objective they are goal oriented of a college education is to produce meant to be view of education kept secret, but (memorizing specific graduates with trained minds. because they are course conten4) to that rarely articulated. Jr of a larger view, i.e. an awareness of what is my view that the student will be better the education process is and how it works. able to keep his or her balance in thecourse Perhaps the most important objective of a and will be better able to gain satisfaction college education is to from the learning process if this "hidden produce graduates with agenda" is brought out trained minds. The The act of thinking requires into the open, demysti- processof acqng a fled ,and dealt with on a trained mind is a process that oper- language. conscious level. ales on several different levels simultane- One of the things that happens simultaneously. On the most obvious level, the student ously with the study of specific course is exposed to a body of subject material and content, is that astudent'svocabulary is expected to memorize it and to answer grows. This is an important part of the pro- questions about it on examinations. For excess of acquiring a trained mind, because ample, in anatomy you will learn the names, the act of thinking requires language; ideas locations, and identifying features of all of cannot be expressed without theaccurate the bones of the body, and you will be use of words. Acquisition of a larger vo- expected to identify them and answer ques- cabulary is especially important in any spe- tions about their features on examinations. cialized subject area such as law or medi- This part of the process is specifically cine. Since anatomy is a foundation course content oriented and is usually the for all medically related studies, thiscourse only process that of study places a lot of MONI=1MINIMIa1111M111ImimmiPOMIN1111110emphasis on words most people are aware of when theyLearning theanatomy of theand word roots. think about a Another part of the course in anatomy. human body is a huge andhidden agenda of h is my belief how- seemingly impossible task.studying specific ever, that there are course content is the several less obvious things happening dur- expectation that by doing so a person will ing the content oriented learning process de- acquire personal organizational skills. This scribed above. is a process that involves learning how to These secondary levels to the process may break a large and complex task clown into smaller parts that are more manageable. be just as important or perhaps even more important than mastery of the actual course For example, learning the anatomy of the content; it may be useful to think of these human body is a huge and seemingly impos-

Lecture Notes Part 1 iii Preface sibk k&a. We begin by breaking thecourse 2. illustrate (give examples down into six units: slatetal system,muscu- or use an lar system, nervous system, histology, and analogy, or visualize, or draw) internal viscera (two units), allowing 3. classify (organize into set and subset) approximately two weeks of time per unit. 4. sequence properly Next we will focus on each in turn, begin- ning by breaking that unit S. compare /contrast (similaritiesIdzffer- down into smaller sec- ences) tions, breaking the sec- 6. be clear about cause tions down into subsec- Break the task down to vs effect tions, and so on. whatyou can do a day 7. analyze parts and furze- Thus far you will be guided at a time. tions by the organization of this book Brief examples of 11&,./ the above thinking and the design of the class schedule, but at skills are used in this anatomycourse some point you will need to develop a per- follow: sonal way of breaking the task down to what you can do a day at a time. The key word in 1. You will be given a precise definition this idea is the word personal. There isno of the term "sagittal",and you will be right or wrong way to develop these man- taught how to identify the lunate bone of agement skills, the process will differ for the wrist. each one of you; you will find yourown 2. During lecture your instructor will unique methods. So, whenever you react to give you an example of a muscle that has college in general and to this course in par- a reversible origin and insertion ticular with the feeling that "it is impossible, there is too much information", or"how can 3. The lecture on joints will be structured I do it?".try to make the shift to "How can around the various ways in which joints Ldo it ? ", and are classified. your answers 4. The chapter Kill come, a day It is believed that the discipline of in this book at a time. using this particular set of skills which describes Finally, the most endochondral important part has much to do with acquiring theossification will of the hidden ability to learn and think. list the steps of the agenda of a col- process in their lege education in the Western tradition is to correct sequence. produce graduates who have acquired a S. When you are studying the autonomic specific set of critical thinking skills that nervous system you will construct a chart are highly valued by Western culture. It is that compares the sympathetic vs the believed that the discipline of using this parasympathetic nervous systems. particular set of skills has much to do with acquiring the ability to learn and think 6. During the lecture on thepancreas you rather than just memorizing information. will learn to distinguish between the Here is a list of these skills, starting with the cause of diabetes and the effect of diabe- most simple tool and ending with the most tes. complex : 7. When you study the centralnervous 1. define (or rianze or identify) system you will analyze the parts of the

Lecture Notes Part I iv Preface CNS in terms of their embryological origin. Your reading, listening, note taking and study efficiency will be greatly improved in any subject if you will watch for the use of these thinking skills, since recognition will immediately signal to you what information is important vs unimportant in terms of course content. You will begin to notice that all textbooks and all lecturesare organized around these principles. Furthermore, since all examinationques- tions are also based on thisspecc approach to organized thinking,you can most efficiently prepare yourseiffor examinations by drilling yourself on information that has been first organized in these specificways. By doing so you will discover thatyou have a very powerful key to academic success. And finally, even more power willcome when you begin to use these skills yourselfto organize a body of informatio,1 thatyou are thinking about or wrestling with. In summary, keep in mind that during the process of studying specific course content in human anatomy, you are simultaneously acquiring a trained mind by theprocesses of expanding your vocabulary, learning to deal successfully with large and complex tasks, and then finally by learninga specific way of thinkino that will liberateyou from blind memorization and regurgitation.

Lecture Notes Part I Preface INTRODUCTION To ANATOMY

In the study of anatomy it is frequently necessary to use adjectives referring to anatomical position and location, including terms for directions and planes. All of these adjectives refer to an individual or an animal which is posed in the sta lard anatomical position. sagittal plane

:'''+' '' In bipedal animals the standard anatomical position is defined as being: in the erect frontal plane stance with the arms hanging vertically by (corona!) the sides, and with the face, toes, and palms forward. See Fig. 1.

In quadrupeds the standard anatomical position is arbitrarily defined as being: all four feet on the ground with the head up and facing forward. See Fig. 2. horizontal plane (transverse) ANATOMICAL superior = above inferior = below anterior = in front posterior = in back proximal = nearest the center or point o' attachment distal = farthest from the center or point of attachment lateral medial = midline or nearer the middle lateral = to the side ventral = belly side or surface dorsal = back side or surface Fig. 1-Biped in Anatomical Position cephalic (cranial) = head area The definitions are as follows: caudal = tail area sagittal - a vertical plane through the long axis that divides the body into right and left ANATOMICAL PLANES (but not necessarily equal halves). Anatomical planes are like imaginary panes frontal- a plane parallel with the long axis of glass slicing through the body in a pre- and at right angles to the sagittal; it separates cisely defined three dimensional direction. ventral from dorsal.

Lecture Notes Part I 110 Introduction horizontal- a plane which is parallel to the horizon. corona! plane (transverse) coronal- aplane that sepa- sagittal plane rates anterior from posterior. transverse - a plane that cuts through the body at right angles to the long axis. A transverse cut through a body or body part is also called a frontal plane cross section (abbreviated (horizontal) x.s.). longitudinal- any plane or cut parallel to the long axis. It could be a sagittal section or a posterior frontal section, or anything in anterior 4 between. A longitudinal section is often abbreviated " I.s.". Fig. 2- Quadruped in Anatomical Position

Study Figures 1 and 2 and notic,?, that for bipeds the frontal plane is also a coronal plane, while for quadru-peds the frontal plane is synonymous with the horizontal plane.

T 12 Likewise notice that for bipeds the trans- hypocho verse plane is also horizontal, while for epigastric driac quadrupeds the transverse plane is synonymous with the coronal plane.

fl%9 umbilical lumbar

TORSO REGIONS hypogastric inguinal Study Figure 3 and notice the following regions of the torso: umbilical epigastric hypogastric Fig. 3- Regions of the Torso lumbar inguinal (iliac) hypochondriac

11 Lecture Notes Part I 2 Introductioo Study Figure 4 and notice the following viscera- the organs of a cavity cavities: parletes - the walls of a cavity thoracic (chest) abdominal peritoneum- the membrane lining the pelvic abdominal and pelvic cavities and reflected cranial over the viscera of those cavities. Because spinal (vertebral) the membrane is reflected, the peritoneum buccal (mouth) hasboth a parietal portion and a visceral nasal portion.

pleura- the membrane lining the thoracic cavity and reflected over thc, surface of the cranial lungs. Thus there is both a parietal pleura and a visceral pleura.

nasal buccal

vertebral cells - the building bin ks of the body. tissues- groups of cells with similar func- thoracic tions. The four basic tissues are: epithelial, connective, muscle and nerve. diaphragm organs - architectural arrangements of tissues functioning together for a common purpose. Most organs are made of all four abdominal tissues, but the tissues are arranged in recognizably different patterns and in different proportions in the various organs. pelvic inlet systems- The organs are grouped together into functional units called systems, suchas the digestive system', the endocrine system, the reproductive systems, the cardiovascular system, etc.

Fig. 4- Body Cavities

Lecture Notes Part 1 3 12 Introduction BONE TERMINOLOGY

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EPIPHYSIS: penetrate into the bone; Some of the blood end area of a long bone vessels from the periosteum penetrate the bone by way of nutrient foramena and DIAPHYSIS: Volkman's canals. center shaft of a long bone PERICHONDRIUM: CANCELLOUS BONE: connective tissue membrane covering spongy bone; having a latticework ar- cartilage; otherwise similar to periosteum chitecture OSTEOBLAST: COMPACT BONE: bone forming cell solid layers of dense ivory like bone OSTEOCYTE: SPICULES: resting bone cell a needle like fragment (in cancellous bone) OSTEOCLAST: MEDULLARY CAVITY: bone removing cell hollow area of the diaphysis CHONDROBLAST: YELLOW MARROW: cartilage forming cell mostly fat; fills the medullary cavity in adult bones CHONDROCYTE: resting or mature cartilage cell RED MARROW: hemopoietic tissue. In the adult it is found in EPIPHYSEAL PLATE: the proximal epiphysis of the femur and The zone of cartilage between the epiphysis humerus, and in the cancellous interior of and the diaphysis in a growing bone long short bones, vertebral bodies, and flat bones bone such as the sternum and cranial vault.

INTRAMEMBRANOUS OSSIFICATION: HEMOPOIETIC TISSUE: bone formation from a membrane model blood forming tissue (forms red blood cells, platelets, and certain kinds of white blood (precu cells) ENDOCHONDRAL OSSIFICATION: OSTEOID TISSUE: bone formation from a cartilage modelor protein component of bone tissue (nonmin- precursor. eralized)

PERIOSTEUM: connective tissue membrane covering bones (except in the areas occupied by articular cartilage); well vascularized, contain:. osteoblasts and blood vessels. Some of the connective tissue fibers (Sharpey's fibers)

Lecture Notes Part I 4 Osteology 13 Ossification

y`;:,:sX :,5 NANV. ':' N'N:.". .,1 e 4 et, " .tip'` 8 7,4:1 A HYPERTROPIBC ZONE : an area of cartilage in which the cells are Flat bones like the bones of the skull are enlarged, swollen and lined up in rows or formed by intramembranous ossification. stacks. Caused by poor nutrient diffusion These bones are first represented by little due to calcification of the matrix as well as pieces of a tough fibrous connective tissue other factors. membrane which are rough patterns for the bone-to-be. Since these membranes are well INES: vascularized and thin, osteoblast activity swelling and bursting of cells. Can be due to starts in the center of the membrane and any number of causes. The area so affected layers of compact bone are formed. is full of cellular debris and is said to be necrotic. Ossification is not complete at birth. The membranes still grow,the fontanels stay PERIOSTEAL BUD: open until approximately 18 months of age, In endochondral ossification: an invasive and the sutures do not close completely until embryonic blood vessel which originates in approximately 8 years of age..Ry this age the periosteum and penetrates into the car- also the bone has been remodeled by osteo- tilage precursor. As it enters it drags osteoclast activity in the center of the diploe blasts with it into the interior of the carti- activity to make it light but still structurally lage. strong (cancellous or spongy bone), and to make more room for the marrow. GROWTH HORMONE: produced in the anterior pituitary gland; stimulates growth of cartilage, bone, and a few other tissues as well.

PITUITARY DWARFISM: Insufficient growth hormone during child- Endochondral ossification begins with a hood, resulting chiefly in small stature. cartilage model of the future bone, This is the method of ossification used for all of the GIANTISM: bones except the flat bones; the long bones Excess growth hormone before closure of Of the body serve as a good example the epiphyses resulting in abnormal height.

ACROMEGALY: BACKGROUND INFORMATION: Excess growth hormone after closure of the epiphyses, caused by tumor of the pituitary , Development of bone from a cartilage and resulting in overgrowth of the flat bones precursor is a dynamic process. To under- and bones of the hands and feet, as well as stand the process, one must first understand that cartilage is avascular, i. e. it does not overgrowth of the skin, contain blood vessels. In fact healthy cartilage contains a chemical which acts as an active inhibitor of blood vessel growth. As a result cartilage cells must obtain their

Lecture Notes Part 1 5 Osteology 14 nutrients by diffusion from the bloodves- c. Old cartilage tends to calcify and calci- sels located in the perichondrium. (Peri- fication slows diffusion. chondrium is the term for the connective tissue membrane surrounding a piece of All three of these eventscause the interior cartilage). In contrast to this, bone is highly cartilage cells to be deprived of nutrients. vascularized, and bone growth will notoc- The distressed cells hypertrophy and then cur unless there is a rich blood supply. lyre. The interior of the cartilage model thus becomes necrotic and isno longer capable Secondly, one must understand that thereare of producing the inhibitor chemical which osteoblasts in the perichondrium. Thusa keeps blood vessels out of the cartilage. collar of bone will begin to be deposited under the perichondrium around the outside As a result a blood vessel from the perichon- of the cartilage model,and the surrounding drium invades into the necroticcenter of the membrane could then just as well be calleda cartilage model. The blood vessel is calleda periosteum. You will find that writers will periosteal bud. It drags osteoblasts from use the terms perichondrium and periosteum the perichondrium in with it, and theosteo- loosely and interchangeably in this situation. blasts settle down on the bits of calcified debris and start depositing osteoid tissue. Third, healthy cartilage is a growing tissue. Osteoid tissue is a protein material that is Thus, cartilage models of future bones will not yet mineralized. It is deposited in the tend to grow larger in size cver time, both in form of spicules, that is, small spinesor length and diameter. needles of bone that interlace withone another in the typical patternseen in spengy or cancellous bone. HE OSSIFICATIONPROCESS] The area of the future bone where all this Turning now to a description of these- activity is taking place is the center portion quence of events in endochondral ossifica- of the shaft or diaphysis. Thus thisarea is tion, and the causes of these events. called the diaphyseal center of ossification. The same identicalsequence of steps will As the cartilage model enlarges diffusion of later take place first in one epiphysis, and nutrients to the cells in the center of the then again, in the second epiphysis (epiphy- cartilage model is compromised due to three seal centers of ossification). factors: Bone deposition spreads outward in all a. the nutrient supply line gets too long, directions from each center of ossification, i. e. the distance between the cells in the replacing cartilage as it goes. In time there center of the cartilage and their source of will remain only a narrow band of cartilage nutrients (blood vessels in the perichon- between the diaphysis and the epiphysis. drium) becomes so great that diffusion to This band of cartilage is called the epiphy- the the central cells is too slow. seal plate of cartilage.

b. the collar of bone deposited around Each long bone will have an epiphyseal the cartilage model slows diffusion and plate of cartilage on each end. Since the puts the cells in the center of the cartilage cartilage in the plates is healthy andgrow- at the greatest risk of not getting suffi- ing, the width of the epiphyseal plate is cient nutrients. increasing. However, at the same time, bone deposition is encroaching from both sides Lecture Notes Part I 6 15 Osteology (from the diaphyseal side and from the epiphyseal side), thus, the observable result is that the epiphyseal plate tends to become narrower and narrower over time. It is as SEQUENCE OF EVENTS: though there were a race between bone growth and cartilage growth, and the bone 1. The cartilage precursor expands. growth is winning over the long haul. 2. Diffusion is compromised in thearea of Ossification proceeds slowly over a 20-25 the diaphysis. year period until all precursor cartilage is replaced by bone. Eventually the epiphyseal 3. Interior cells become necrotic. plate of cartilage is completely obliterated; this is called closure of the epiphyses, and 4. A periosteal bud invades. growth of that bone stops. In other words, lengthwise growth of a bone is accom- 5. Bone is deposited in the interior of the plished by expansion of the epiphyseal diaphysis. plates, and when the epiphyses close there can no longer be expansion. 6. These same steps are repeated in each epiphysis. As the bone is growing it is simultaneously being remodeled. A medullary cavity is 7. The epiphyseal plates close, and growth hollowed out of the interior of the diaphysis, stops. and the orientation of the bone changes when the stresses on the bone change. The cells which do the remodeling are the osteo- CAUSE/EFFECT: clasts. 1. Diffusion: Three factors interfere with Bone growth is affected bymany different diffusion of nutrients to the cartilageprecur- hormones. Among these is an anterior sor: pituitary hormone known as growth a. A the diameter of the model increases hormone (GH). Too much growth hormone the cartilage cells in the center get too far before closure of the epiphyses will cause from the source of supply. giantism. Not enough growth hormone will b. The periosteal collar of bone actsas a cause dwarfism. Too much GH after clo- barrier to diffusion. sure of the epiphyses will cause acromegaly c. Old cartilage matrix calcifies. ,in which the individual does not growany taller, but does show continued skeletal 2. Necrosis: When cartilage cellsare de- growth in certain of the short bones of the prived of nourishment they will hypertrophy hands and feet, and in the flat bones of the (swell), arrange themselves in rows, and sternum and skull and face. Thus in then lyse (burst apart and die). acromegaly the person's features become distorted due to over growth of some but not 3. Periosteal Bud: Dying cartilage cellsno all aspects of the skeleton. longer produce chemical inhibitors to keep blood vessels out, therefore the periosteal bud enters.

4. Interior Ossification: The invading peri- °steal bud drags with it osteoblasts from the

Lecture Notes Part I 7 Osteology 16 periosteum, thus ossification can begin in th,.... interior.

5. Epiphyseal Plate: The epiphyseal and diaphyseal centers of ossification expand toward one another. The zone of growing cartilage remaining between them is called the epiphyseal plate.

6. Closure of the epiphyses occurs because the growth rate of cartilage in the epinhyseal plate Is slower than the rate at which it is being replaced by bone on both edges. The result is :hat solid bone eventually replaces the epiphyseal plate of cartilage. and growth stops.

Lecture Notes Part 1 8 17 Osteology '

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: "z..,;, FOOT eversion inversion FLEXION: Flexion decreases the angle between two CIRCUMDUCTION: bones (brings 2 bones closer together). Technically circumduction involves flexion, abduction, extension, and adduction in that EXTENSION: sequence, as when the arm describes a cone. Extension increases the angle between twoi

' -.::- t..;;,'k '4 -s- ...; \:->:*.''K bones (moves 2 bones farther apart). i'..:.,,*:,,i, :..U.'...W..:::-`s.is.i. .'kel. ,1 . . 4. ,,,, T 1.-,Nt,dt, , "'ASV.. tik There are several special cases of flexion/ x4, extension: BURSAE HAND A bursa is a closed sac lined with synovial Dorsiflexion (true extension) membrane found where soft tissues presson Palmar flexion (true flexion) bone during movement. Examples: subdel- toid bursa; olecranon bursa. FOOT Dorsiflexion (true flexion) Plantar flexion (true extension) TENDON Sh2ATHES A tendon sheath is a closed synovial sac SHOULDER & HIP lying between a tendon and a bone, protect- The ball and socket joints of the shoulder ing the tendon as it moves against the bone, and hip move so freely that the defini- especially when held close to the bone by a tions of flexion and extension need to be connective tissue retinoculum. Example: the broadened. In these locations the defini- hand and the foot each contain many tendon tion of flexion is any movement in an sheaths as well as several retinacula. Ten- anterior direction and extension is any dosynivitis is a condition in which the movement in a posterior direction. tendon sheath is inflamed and tender.

ABDUCTION: Abduction is movement away from the midsagittal axis of the body or the central axis of a part. Examples: abduction of the arm; abduction of the fingers.

ADDUCTION: Opposite of the above

ROTATION: Rotation is movement of a body part around an axis or pivot point. Rotation is basically either medial rotation or lateral rotation. There are several special cases of rotation.

HAND: supination proration

Lecture Notes Part I 10 19 Arthrology Specific Joint Features

Strong medial and lateral collateral ligaments strengthen the hinge joint. These The shoulder joint has little anatomical ligaments can also be called the ulnar and stability because the glenoid fossa is so radial collateral ligaments. shallow. Thus the shoulder is frequently dislocated. The joint capsule attaches to the rim of the glenoid fossa, and to the anatomical neck of the humerus.

MUSCULOTENDONOUS CUFF: TN,muscles surrounding the shoulder joint give it most of its strength. The tendons of four of these muscles attach to the greater and lesser tubercles of the humerus, forming a cuff around the anatomical head. This cuff group will be emphasized during the unit on muscles. Fig. 7- Right Elbow Joint, Lateral View

is a common jomt cavity forthe lunge joint between the ulna and the humerus, and for the pivot joint between the head of the radius and the ulna.

COLLATERAL LIGAMENTS: The most unusual one is the annular ligament which embraces the head of the radius and within which the radius rotates freely for pronation and supination. See Figs. 6, 7, 8.

Fig. 80- Right Elbow Joint, MedialView showing medial collateral ligaments

The head and neck of the femur are entirely enclosed in the joint capsule. Inside the joint is the ligamentum teres (also called ligamentum capitis) which is attached to the Fig. 6- Right Elbow Joint, Anterior Vim fovea capitis of the head of the femur. The ligamentum teres does not hold the joint

Lecture Notes Part I 11 A rth rdIOLV 20 together, in fact it bears no strain at all, COLLATERAL LIGAMENTS: rather it provides safe passage for the ves The strongest reinforcement is anteriorly. sels and nerves supplying the head of the The iliofemoral is the most important. femur. See Figs. 9.10.

antrzior iliofemoral ligament joint capsule

Fig, 9- Right Hipiloint Fontal Section Fig. 10- Right Hiputoint, AnteriorView

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The following ligaments are the most important ones in the sacral region: Sacroliliac Sacrospinous Sacrotuberous

sacmspinous

sacrotuberous

Fig. 11- Sacral Ligaments, Medial View Fig. 12- Sacral Ligaments, Medial View

Lecture Notes Part I 12 Arthrology 21 tibial tuberosity The patellar tendon or ligament is part of anterior cruciate ligament the tendon from the quadriceps femoris medial muscle of the anterior thigh. The patella meniscus lateral changes the angle of pull of this tendon. It is meniscus a gliding joint. Notice that there is no articu-

lation between the patella and the tibia. lateral collateral ligament medial k,. k collateral ligament posterior cruciate ligament One of the most interesting features of the knee joint is that it contains several Fig. 14- Right Knee, SuperiorView intracapsular ligaments, the most important of which are the cruciate ligaments. There is an anterior eradiate and a posterior crud- COLLATERAL LIGAMENTS: ate. They connect the condyles of the femur The medial and lateral collateral ligaments to the opposite condyles of the tibia. There can also be called the tibial and fibular are also several other menisco-femoral liga- collateral ligaments. They strengthen the ments. joint capsule, but probably the most important source of additional strength and stability are the muscles and fascia of the thigh which extend down to the knee.

menisco- posterior anterior femoral medial cruciate ciate ligament meniscus lateral meniscus

lateral Fig. 13- Right Knee, Anterior View collateral ligament medial tibia collateral The knee joint has great weight bearing ligament capacity and considerable stability It's stablility is largely due to the presence of halfmoon shaped menisci (seminar carti- Fig. 15- Right Knee, Posterior View lages). These cartilages are thicker on their outside edges and much thinner on their medial borders, thus both surfaces are concave.

Lecture Notes Part I 13 Arthrology 22 Mostly Flexion/Extension. The weight shifts back for flexion and forward for extension. There is some medial and lateral rotation. Locking the Knee refers to shifting forward to full extension plus a slight amount of medial rotation. The locked knee provides great stability.

In spite of it's stability, the knee is quite prone to injury, especially when in the extended and fully weight bearing position. Damage to a meniscus is common, especially the medial meniscus since it is attached to the tibial collateral ligament, and if the ligament is torn it will often damage the meniscus as well.

Most injury to the knee is the result of body-contact sports, but it can also happen in running if something causes the runner to turn an ankle (eversion of the foot often results in lateral flexion of the knee, which stresses the medial ligaments and the vulner- able medial meniscus).

MOST COMMON FRACTURES:

Adduction Fracture Abduction Fracture Compression Fracture Fracture of the Tibial Spine

Lecture Notes Part I 14 '23 Arthrology Gross Anatomy of Muscles

The origin of a muscle is often attached directly to the periosteum of a bone, without The three attributes of a muscle that are any tendon. The insertion is usually by way usually emphasized in a lecture and in of a tendon. However some muscles have reference books are action, mien, and in- tendons on both ends. sertion. Of these three the most important Most tendons are shaped like cords or attribute is action. straps. However some muscles have a thin aponeurosis, which is actually a broad ORIGIN & INSERTION flattened sheet-like tendon connecting muscle to muscle or muscle to bone. The origin of a muscle is the stationary end. Examples: aponeurosis of the external The insertion is the end which is most abdominal oblique and latissimus dorsi. moveable. Tendons connect muscle to bone, whereas As a muscle shortens the insertion is pulled ligaments connect bone to bone. toward the origin, and the action is movement at whatever joints the muscle crosses. There are three ways to name the action: by ACTION the joint name, by the body part name, or by The action of a muscle refers to the kind of the name of the bone. For example: flexion movement that a muscle causes at a joint. of the hip = flexion of the thigh= flexion of the femur. Muscles do work only when they contract or shorten. Stretching is passive and does The origin and insertion are sometimes not do work. interchangeable, depending on which end is The prime mover is the primary agent being held still by other muscles or by causing any given movement. gravity. For example, rectus abdominis can cause anterior flexion at the waist in differ- A synergist is a muscle which helps the ent ways, depending on whether you are prime mover in some way. It may stabilize standing, or hanging by your arms from a the origin or it may cause the same action on bar, or lying on your back and bringing your the same joint as the prime mover. hips up toward your head. An antagonist is a muscle whose move- A muscle may have two or more origins. ment counteracts the action of any given This multiple head arrangement gives a sides of a joint from one another. When the muscle more power while still concentrating prime mover is contracting the antagonist full force on a single spot. Example: biceps must relax. prime mover. Antagonists are on brachii or quadriceps femoris. opposite sides of a joint from one another. When the prime mover is contracting the A muscle may have two or more inser- an- tagonist must relax. tions. This arrangement spreads the action over several joints. Example: extensors and flexors of the digits.

Lecture Notes Part I 15 Muscular System 4 Muscles of the Head

The muscles o; the head a.: divided into two groups basedon common characteristics within the group. These two groups are the muscles of facial expression and the muscles of mastication.

Fig. 17- Some Muscles of Facial .% Fig. 16- Muscles of Facial Expression Expression and Mastication 1. frontons 7. mentalis 2. orbicularis oculi 8. depressor anguli oris superior 3. nouli.s 9. buccinator nuchal line sternocleido- 4. zygomaticus major 10. sternocleidomastoid mastoid 5. orbicularis oris 11. masseter splenius capitis 6. depressor labii inferioris12. trapezius trapezius 13. temporalis

Fig. 18- Occipitalis MUSCLES OF FACIAL EXPRESSION

The muscles of facial expression are unique in that they insert skin rather than on FRONTAL'S bone. They are used for nonverbal communi- I: forehead at eyebrow level cation. All of the muscles of this group are A: eyebrow flash greeting innervated by Cranial Nerve VII, the Facial See Figs. 16, 17. Nerve. PROCERUS OCCIPITAL'S I: area between inner corner of eyebrows I: skin in occipital region A: horizontal folds between eyebrowsas in A: wrinkles scalp in occipital region frowning See Fig. IS. See Fig. 17.

Lecture Notes Part I 16 Muscular System 1Z5 CORRUGATOR I: inner corner or eyebrow from diagonal DEPRESSOR LABII INFE'llORIS angle above eyebrow I: all along lower lip, from below A: vertical folds above inner corner of eye A: pulls lip down as in grief or a pout as in frowning See Figs. 16, 17. See Fig. 17. MENTAL'S ORBICULAR'S ()CUL' I: point of chin I: surrounds eye like a sphincter A: wrinkles skin over chin as in grief,pout A: squinting as when light is bright See Fig 16. Set Figs. 16, 17. BUCCINATOR NASAL'S This is the deep muscle of the cheek. I: bridge of nose A: suction. See Fig 16. A: wrinkles skin over bridge of nose as in PLATYSMA disgust A: grimacing as in fear or grief See Fig. 17. Not illustrated. LEVATOR (QUADRATUS j LABII SUPERIORIS 0: 3 or 4 separate slips of muscle I: upper lip A: pulls lip out and up as in kissing See Fig. 16. All of the muscles in this group inserton the mandible. They are all innervated by the mandibular division of Cranial Nerve V, the LEVATOR ANGULI ORIS Trigeminal Nerve. The action of all is I: corner of mouth, from above chewing. A: lifts corner of mouth as in smiling Not illustrated. TEMPORAL'S ZYGOMAT1CUS MAJOR 0: temporal region of skull 0: zygomatic bone I: coronoid process of mandible I: corner of the mouth A: chewing See Fig 16. A: lifts corner of mouth as in broad smile MASSETER See Figs. 16, 17. 0: zygomatic arch RISORIUS I: angle of the jaw I: corner of mouth from horizontal angle A: chewing See Fig 16. A: slightly lifts corner of mouth as infaint MEDIAL PTERYGOID smile. See Fig 17. 0: medial pterygoid plate of sphenoid; I: ORBICULAR'S ORIS medial aspect of anglt of jaw I: all around mouth like a sphincter A: grinding movements of chewing A: puckering of mouth as in kissing or Not illustrated. pensiveness or indicating LATERAL PTERYGOID disapproval. See Figs. 16, 11. 0: lateral pterygoid plate of sphenoid; I: DEPRESSOR ANGULI ORIS medial aspect of angle of jaw I: corner of mouth from below A: grinding movements of chewing A: pulls corner of mouth down as in grief Not illustrated. and sadness See Figs. 16, 17.

Lecture Notes Part I Muscular System 4M. 9 0

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1 A:extension or lateral flexion of head and neck See Figs. 18, 20, 31.

CONTENTS OF THE TRIANGLE Memorize the muscle positions in the triangle, from top to bottom.

SPLENIUS CAPMS 0:spinous processes of cervical vertebrae I: superior nuchal line of occipit A:extension or rotation of head and neck, See Fig. 20.

LEVATOR SCAPULAE 0:transverse processes of cervical vertebrae I: superior angle of scapula A:shrug shoulder at extend head and neck, or lateral flexion of head and Fig. 20- Posterior Triangle two Neck neck See Figs. 20, 31.

SCALENUS MUSCLES Learn these (3) as having a group ori- scalenus gin, insertion and action. posterior 0: transverse processes of cervical scalenus rnedius brachial vertebrae plexus I: 1st and 2nd nerves A: deep inspiration (elevates the ribs) scalenus See Figs. 20, 21. anterior subclavian artery clavicle

SCALENUS MUSCLES manubrium These were introduced with the posterior of sternum triangle of the neck. See Figs. 20, 21.

EXTERNAL INTERCOSTALS Fig. 21- Scalenus Muscles 0:bottom edge of the upper rib I: top edge of the lower rib The fiber direction is diagonally downward toward the mid line. I: bottom edge of the upper rib A: elevates the lower rib. All work together The fiber direction is diagonally upward to raise the rib cage for inspiration See Figs. toward the mid line. 21, 27. A: pulls the upper rib down. All work INTERNAL INTERCOSTALS together to lower the rib cage for expiration 0: the top edge of the lower rib See Fig. 28.

Lecture Notes Part I 19 Muscular System 28 DIAPHRAGM This dome shaped muscle is unique. All the fibers start from below and rise towards a central tendinous area at the top of the dome. ERECTOR SPINAE 0: very widespread, in a complete ring spinalis, longissimus around the interior wall of the torso I: central tendon of the diaphragm The erecter spume group is the main posture A: Contraction causes the dome to flatten, muscle of the spinal column. It is not neces- which enlarges the thoracic cavity increas- sary to learn the names of the muscles in ing its negative pressure and causing inspira- small print, instead learn the action for the tion. During relaxation the diaphragm takes group as a whole. See Fig. 23. on its dome shape again, reducing the chest cavity and causing expiration. See Fig. 22. SEMISPINALIS CAPITIS semispinalis cervicis semispinalls thoracis sternum Semispinalis capitis is the deep posture muscles (group) of the neck. Superficial head and neck posture muscles were considered previously. See Fig 23.

superior nuchal line

Fig. 22- Diaphragm, Midsagittal View

erecuit; spinae A posture muscle is an antigravity muscle; it holds the body erect by resisting the pull of ,4461k1; gravity. Any muscle which acts as an exten- .01 sor at a weight bearing joint is a posture ;31 'le 1 muscle. I 6. 14j IVO ttin- 7 The extensors of the neck (head) and spine

At% tie (back) therefore qualify as posture muscles. r s ; The ones we have covered so far are: t clavotrapezius, splenius capitis, and levator scapulae. Next we will consider the Fig. 23- Deep Muscles of the Back deep posture muscles of the back and neck.

Lecture Notes Part I 20 Muscular System 29 Muscles of the Posterior Abdominal Wall

PSOAS MAJOR Most people have a psoas minor, but it is ins.gmlicant and in fact is absent in about 20% of the population. If present its tendon will be seen as a flat white shinning ribbon on the anterior surfac3 of psoas majer. 0: sides of the bodies of lumbar vertebrae I: lesser trochanter of the femur A: flexion of the hip or flexion of the trunk See Fig. 24.

ILIACUS 0: iliac fossa I: lesser trochanter of the femur A: flexion of the hip See Fig. 24.

ILIOPSOAS The iliacus and psoas muscles start separately, but soon their tendons fuse and have a common insertion and action. The fused portion is called the iliopsoas muscle. See Fig. 24.

QUADRATUS LUMBORUM 0: iliac crest I: lower ribs

A: lateral flexion of the trunk. Fig. 24 Muscles of the Posterior See Fig. 24. Abdominal Wall, Anterior View

Lecture Notes Part I 21 Muscular System 3 0 MUSCLES OF THE ANTERIOR ABDOMINAL WALL

In addition to whatever else they do, the muscles of the anterior abdominal wall all 1. rums abdominis act to compress the abdomen. Compression of the abdomen is necessary to hold the viscera in place, and to aid in such func- 2. lines alba tions as : forced expiration, coughing, sneezing, vomiting, defecatio-i, urination, and parturition

RECTUS ABDOMINIS MUSCLE There are two rectus muscles. They lie next 3. tendinous inscriptions to one another on either side of the linen alba. The fibers run vertically but are inter- rupteii periodically by transverse fibrous 4. inguinal ligament bands called the tendinous inscriptions (a.k.a. tendinous interruptions; tendinous 5. external inguinal ring insertions). See Fig. 25.

Sheath of the Rectos Since there is nc bone to attach to in the Fig. 25- Rectus Abdorninis front of the abdomen, the aponeuroses of the three anterior- lateral abdominal muscles pass across the surface of the rectus on their way to the midline where they meet and fuse with those of the opposite side, forming the lines alba Because of this arrangement, the rectus is covered by layers of connective tissue known as the sheath of the rectos. The Fig. 26- Sheath of Rectus I. rectus abdominis precise anatomy of these layers is important 5. tranfversus 2. Linea alba 6. aponeurosis of ext. oblique surgically: See Fig. 26. 3. external oblique 7. aponeurosis of int. oblique 4. internal oblique the aponeurosis of external oblique 8. aponeurosis of transversus passes anterior to rectus; the aponeurosis of the transverse muscle passes posterior to rectus; Fiber Direction the aponeurosis of internal oblique splits, half passing anterior and half The antero-lateral abdominal musclesare posterior to the rectus. layered to reinforce one another. It is not necessary to memorize the extensive origins of these lateral muscles, instead learn to recognize them by their fiber direction.

Lecture Notes Part I 22 Si. Muscular System EXTERNAL OBLIQUE MUSCLE The fibers of external oblique run diagonally down and toward the midline vine the direction of your fingers when putting your hands in the side pockets of a pair of jeans). 0: widespread, but basically from theexter- 9. internal intercostal nal surfaces of the lower 8 ribs. I: linea alba (and crest of ilium) 10. internal oblique A: compression of the abdomen and trunk 11. aponeurosis of rotation. See Fig. 27. internal oblique

6. external intercostal

7. external oblique Fig. 28- Internal Oblique 8. aponeurosis of external oblique

Fig. 27- External Oblique

INTERNAL OBLIQUE MUSCLE The fibers of the internal oblique run diagonally up and toward the midline. 0: lateral half of inguinal ligament, iliac crest, and lower ribs. --wM I: linea alba A: compression of the abdomen, and trunk rotation See Fig. 28. 14

TRANSVEFtSUS ABDOMINIS Fig. 29- Trans versus Abdominis The fibers of transve. sus run horizontally. 0 inguinal ligament, iliac crest and lower 12. transversus ribs. I: linea alba 13. aponeurosis A: compression of the abdomen, and trunk 14. spermatic cord rotation See Fig. 29.

Lecture Notes Part I 23 Muscular System 3 DESCENT OF THE TESTES

INGUINAL LIGAMENT The inguinal ligament marks the dividing external oblique Ilea alba sheath of roc line where wall of abdomen stops and thigh begins. It extends from the anterior superior iliac spine to the pubic tubercle, and is fanned by connective tissuethat blends with the lower free edge of the external oblique biguinal ligament aponeurosis. See Figs. 25, 30. external inguinal ring

INGUINAL CANAL & RINGS The inguinal canal is a tunnel that passes through the layers of the abdominal wall Fig. 30- inguinal Ligament gradually one by one rather than directly through all three at once. The internal opening of the tunnel is called the deep in- CREMASTER MUSCLE guinal ring. The superficial opening is As the testicle descends, some of the fibers called the external inguinal ring. of internal oblique get hooked around the See Figs. 25, 30. testicle and dragged down into the scrotum. These loops of muscle are called the cremas- GUBERNACULUM ter muscle. Contraction of the cremaster can The gubernaculum is an embryological con- draw the testicle up into the abdomen in nective tissue cord that is attached to the infants. Sumo wrestlers have been trained gonad, passes through the inguinal canal, since infancy so that they retain this ability and then attaches to the inside of the scro- as adults. tum (in the male) or labia majora (in the female). In the male this cord shortens HERNIA shortly before birth, pulling the testicle out A hernia is any protrusion of an internal of the abdomen, down thru the inguinal organ into a cavity where it is not normally canal, and into the scrotum. found.

INDIRECT HERNIA SPERMATIC CORD An indirect hernia refers to protrusion of The spermatic cord remains attached to the a loop of intestine through the inguinal testicle and therefore it occupies the inguinal canal into the scrotum. It may be caused canal in the male. See Figs. 29, 30. by anything which increases abdominal pressure, and it usually only happens in CRYPTORCHIDISM males, presumably because the inguinal Cryptorchidism means hidden testicle, and it canal is somewhat more open in males. refers to failure of the testicle to descend. The condition is easy to correct surgically. If DIRECT HERNIA not corredted, the adult male will be sterile A direct hernia refers to a protrusion of because the temperature inside the abdomen intestine through a tear in the abdominal is too high for the production of sperm cells wall. It can be caused bya blow to the although testosterone production will not be abdomen, or by weakness of the abdomi- affected. nal muscles.

Lecture Notes Part I 24 33 Muscular System Mooring Muscles of Scapula

The only place in the pectoral girdle where ligaments hold bone fo bone is between the All of the muscles in this group originate clavicle and sternum, elsewhere only on the axial skeleton and insert on the muscles hold the shoulder girdle in place on scapula. Notice that they approach the the axial skeleton. The reason for this scapula from every possible direction. highly unusual situation is the necessity for very free movement of the arm. superior nuchal line

levator scapulae

clavotrapezius

rhomboideus minor acromiotrapezius

spinotrapezius rhomboideus major

rhomboideus major

serrates anterior latissirnus dorsi 14

external abdominal oblique

Fig. 31- Mooring Muscles of the Scapula. Superficial muscles +re shown on the left side. Deep muscles are shown on the right side.

Lecture Notes Part 1 Muscular System 25 4 TRAPEZIUS This muscle has three sections that can act separately due to separate innervations. clavotrapezius ac romlotrapezlus spinotrapezius 0:superior nuchal line, ligamentum nuchae and spinous processes of all thoracic vertebrae I: clavicle, acromion, and spine of scapula A: elevation, adduction, and depression of scapula. Extension and lateral flexion of head and neck. See figs. 31, 16, 18, 20, 33.

RHOMBOIDEUS MAJOR & MINOR 0:spinous processes of thoracic vertebrae I: vertebral border of scapula A: adduction of scapula See fig. 31. Fig. 32- Serratus Anterior LEVATOR SCAPULAE 0:transverse processes of upper cervical vertebrae cleidomastoid I: superior angle of scapula acromiotrapezius A: elevates scapula (shrug shoulder). Exten- sion and lateral flexion of neck ac-romio- stemomastoid deltoid See figs. 20, 31.

SERRATUS ANTERIOR 0:front surface of ribs I: vertebral border of scapula A: abduction (protraction) of scapula (im- pcctoralis portant in pushing) major See figs. 31, 32, 39.

PECTORAL'S MINOR 0:front of ribs I: coracoid process of scapula A: stabalizes scapula See fig. 33.

Fig. 33- Pectoralis Minor Pectoralis major has been removed.

Lecture Notes Part I 26 Muscular System 35 Muscles acting on Shoulder Joint

SUBSCAPULARIS 0: subscapular fossa I: lesser tubercle of humerus All of the muscles in this group originate A: medial rotation of humerus and extension of on the axial skeleton and insert on the head humaus See Fig. 35, 41 of the humerus. They form a musculoten- dinous atfaround the head of the humerus, helping to hold it in its socket. They all act on the humerus.

1. s

1.-1 4000p--Nttriusq. Fig. 35- Shoulder Girdle, Anterior View , inserts on anterior surface woo of humerus 444 4. toms major .CL

Fig. 34- Rotator Cuff Muscles Included in this group are the power Right Arm, Posterior View muscles which of the ann. They all originate on scapula and/or clavicle and insert on SUPRASPINATUS upper shaft of humerus. 0: supraspinous fossa of scapula I: greater tubercle of humerus As a rule, any muscle which is a flexor or A: abduction of humerus extensor of the arm will also act as an See Figs. 34, 38, 41 adductor of the arm.

INFRASPINATUS DELTOID 0: infraspinous fossa of scapula This muscle has three separate sections that I: greater tubercle of humerus can act separately due to separate innerva- A: lateral rotation and extension tions: See Figs. 34, 38, 41 Acromiodeltoid Clavodeltoid TERES MINOR Spinodeltoid 0: axillary border of scapula 0: clavicle, acromion process of scapula, I: greater tubercle of humerus and spine of scapula A: same as infraspinatus I: deltoid tuberosity of humerus See Figs. 34, 38, 41

Lecture Notes Part I 27 Muscular System 36 A: See Fig. 33, 36, 37, 38, 39, 41. Acromiodeltoid: abduction concentrates great force on a small area Clavodeltoid: flexion, Aducdon, 0: low back vertebrae by way of the lum- medial rotation bodorsal aponeurosis Spinodeltoid: extension, adduction, bicipital groove, anterior humerus lateral rotation A: extension, medial rotation and adduction of humerus See Figs. 31, 41

supraspinatus 0041,"vae.se insertion / _Ap Pa..... r cr:v Jr Se.s. \s scapula

deltoid Fig. 36 -Deltoid, Anterior View insertion

1/4 brachialis insertion

Fig. 38- Teres Major, Posterior View

old PECTORALIS MAJOR This muscle forms the anterior wall of the axilla. It has four overlapping heads 0: clavicle, sternum and ribs I: lateral crest of the bicipital groove A: flexion, medial rotation, adduction See Figs. 31, 41.

Fig. 37 -Deltoid, PosteriorView clavicular head of pectoralis major TERES MAJOR sternal heads of 0: inferior angle. of scapula along axillary pectoralis major border. bicipital groove (medial crest ) A: same as latissimus dorsi See Fig. 34, 38, 41.

LATISSIMUS DORSI This muscle forms the posterior wall of the axilla. It is flat and sheetlike; it has a wide- 1 spread origin and a small insertion, hence it Fig. 39- Pectoralis major Lecture Notes Part 1 28 Muscular System 37 CORACOBRACHIALIS 0: coracoid process of scapula I: shaft of humerus, A: flexion and adduction of humerus See Figs. 40

Fig. 40- Coracobrachialis, Anterior View

infraspinatus subscqularis tares minor (lesser tubercle) intertubercular groove (bicipital groove tares major latissimus pectorals dorsi major

Fig. 41- Major Insertions on Proximal End of Humerus, Anterior View

Lecture Notes Part 1 29 Muscles Actingon the Elbow Joint

The flexors are on the anterior side of the bicipital groove rod.11. . coracold process elbow; the extensors are on the posterior Ai---040, side. latissimus dorsi biceps tendon insertion it111 During supination and pronation of the 11. rI, -..:coracolvachialis forearm the ulna remains stationary while teres major the radius rolls over the top of the ulna. As a insertion result all supinator and pronator muscles must insert on the radius. i deltoid, insertion BICEPS BRACHH brachial 0: short head: cora- artery coid process of scapula; long head: supragle- sh"t head noid tubercle of brachialis scapula. The tendon of this head lies in the bicipital groove of the humerus. bicepsI: tuberosity of radius brachii and ulnar aponeurosis A: flexion of el'oow and supination of supinat forearm, also flexion at shoulder See Figs. 41, 42, 44. Fig. 42- Brachialis Anterior View Right Arm

Fig. 41- Biceps brach!! brachioradialis Anterior View Right Arm

BRACHIALIS: 0: lower half of shaft of humerus

I: coronoid process of ulna and ulnar tuber- pronator osity teres A: flexion of elbow See Fig. 42

BRACHIORADIALIS 0: lateral epicondyle of humerus pronator I: styloid process at distal end of radius quadratus A: flexion of the elbow and supination of Fig. 43 Brachioradialis. forearm Anterior View Right Arm See Figs. 43, 44.

Lecture Notes Part 1 30 Muscular System 3 9 PRONATOR TERES ANCONEUS 0: medial epicondyle of humerus 0: lateral epicondyle of humerus I: shaft of radius I: ulna A: pronation of forearm; flexion of elbow A: extension of elbow See Figs. 43, 44. See Figs. 45, 46.

Fig. 45- Triceps Brachii, Fig. 44- Right Elbow, Anterior View Right Arm, Posterior View

PRONATOR QUADRATUS 0: distal shaft of ulna I: distal shaft of radius A: pronation of forearm See Fig. 43.

SUPINATOR lies deep to the brachioradialis 0: lateral epicondyle of humerus I: upper shaft of radius A: supination of forearm See Fig. 42.

TRICEPS BRACHI' three heads of origin 0: long head: scapula, infraglenoid medial head: proximal humerus lateral head: distal humerus I: olecranon process of ulna A: extension of elbow See Fig. 45. Fig. 46- Anconeus, Right Arm, Posterior View Muscles actingon Wrist & Finger Joints The muscles which originate on the medial epicondyle are flexorsor pronators. The muscles which originate on the lateral epicondyle are extensors or supinators. Brachioradialis ispar- tially an exception in that its origin is the lateral epicondyle; it is a flexor & alsoa supinator. Rule to follow when identifying muscles of the forearm: first identify and mentallyset aside brachioradialis and pronator teres. They do not act on the wristor fingers. The flexors of the wrist and fingers are on the anterior surface and generally originateon or near the medial epicondyle of the humerus. The extensors are posterior or lateral and originateon or near the lateral epicondyle. The flexors and extensors of the wrist and fingers havea minor action at the elbow and you do not need to memorize it.

All of these muscles originate on the medial epicondyle of the humerus and all act to flex the wrist and elbow.

PALMARIS LONGUS FLEXOR DIGITORUM 0: =dial epicondyle superficiais & I: palmar aponeurosis protundus A: flexion of wrist and 0: medial epicondyle elbow I: four fingers (not the See Fig. 49. thumb) FLEXOR CARPI A: flexion of fingers, interosseous wrist and elbow ULNARIS membrane See Fig. 48. 0: medial epi- X01" condyle digi I: wrist (carpus) on little finger side. interosseous A: flexion of wrist and memtrane elbow and adduction of wrist t See Figs. 47, 49. flexor carpi ulnaris FLEXOR CARPI .) 'pi 46:f.. RADIALIS e IT } 41 el 0: medial epicondyle t. I: wrist (carpus) on thumb side A: flexion of wrist Fig. 47- Flexor Carpi Fig. 48- Flexor Digitorum and elbow and Right Forearm, Anterior View Ulnaris abduction of wrist Right Forearm, Anterior View See Fig. 49.

Lecture Notes Part I 32 Muscular System 4 1. ribs 1.N. ; . .4 1

: 1 ....., I. 1t li, "..---. i.. \...... ,Cr A.:...... 50'. i r.0. Ori,s. r" ire*".t ... s 4144,Y"' go 1 1 ... .a : f at ".: 4C I . it F I 1 fr. 4.4median nersin pisiform g carpal turiffel bone /*radial flexor carpi artery Wrath

1 flexor carpi tibiar neve, radialis ulnar artery palmaris longus Fig. 50- Superficial Extensor Tendons Fig. 49- Superficial Flexor Tendons tendons are protected by tendon sheaths as they pass under the extensor retinaculum Right Wrist

EXTENSOR DIGITORUM communis and indicis 0: lateral epidcondyle All of these muscles originate on the I: all four fingers (not the thumb) lateral epicondyle and all act to extend the A:extension of wrist and fingers wrist and elbow. See Fig. 50. EXTENSOR CARPI RADIAL'S LONGUS EXTENSOR DIGITI MINIM (QUINT') 0:lateral epidcondyle 0:lateral epidcondyle I: wrist, thumb side I: little finger A:extension and abduction of wrist A:extension of wrist and 5th finger See Fig. SO. See Fig. 50. EXTENSOR CARP! RADIAL'S BREVIS 0:lateral epidcondyle I: middle of wrist A:extension of wrist See Fig. 50. extensor carpi ulnaris EXTENSOR CARPI ULNARIS 0:lateral epidcondyle I: wrist, little finger side &En A: extension and adduc- ;*-- tion of wrist See Fig. 50, 51. Fig. 51- Extensa 'arpi Ulnaris Right Forearm, Dorsal View Lecture Notes Part I 33 Muscular System 1'42 EXTENSOR POLLICIS LONGUS See Fig. SO, St

All the muscles in thisgroup originate on EXTENSOR POLLICIS BREVIS the radius and all inserton the thumb. The See Fig. 50, 52. name of the muscle indicates its action. ABDUCTORPOLLICISLONGUS The tendons of extensor carpi radialis longus and brevis tunnel under theextensors FLEXOR POLLICIS LONGUS and abductor of the dumb When the thumb is forcibly abductedand extended a hollow fossa called theanatomi- cal spud boxappears at the base of the thumb. It is created by the tendons ofthose muscles.

extensor pollicis longus extensor pollicis brevis

on,b)

Fig. 52- Extensor Pollicis Longus& Brevis Right Forearm, Posterior View Extensor pollicis longus is shownas transparent where it overlies Extensor pollicis brevis. Muscles of the Hip and Thigh .i tac crest, sacrum, an. coccyx I: shaft of femur below greater trochanter, & ilio tibial tract The tough thick investing fascia of the A: extension and/or lateral rotation of the lateral thigh is called the fascia lata. Part of hip, also abduction of leg and bracing of the this fascia is especially tough and thick and extended knee is called the iliotibial tract or iliotibial See Figs. 53 and 60. band. This band extends from the crest of the ilium to the lateral condyle of the tibia; GLUTEUS MEDIUS it acts as a kind of tendon for two of the 'Mink of this muscle as homologousto the muscles of the gluteal group. deltoid muscle of the shoulder. It has three sections, (part 1. anterior; part 2. middle; part 3. posterior), which can act separately. 0: crest of ilium I: greater trochanter A: part 1: medial rotation, flexion; part 2: abduction; part 3: extension, lateral rotation See Fig. 53.

GLUTEUS MINIMUS 0: posterior surface of ilium I: greater trochanter A: medial rotation and abduction Not illustrated.

DEEP GLUTEAL GROUP pisiformis gemellus superior obturator internus Fig. 53- Lateral View, Left Leg gemellus inferior obturator externus TENSORFASCIA LATA quadratus femoris 0: anterior superior iliac spine Learn these as a group, not individually. All I: iliotibial tract of the muscles in the group are small, all A: flexion of hip; tightens the iliotibi,tract pass behind the hip joint, all insert on the and therefore helps brace the knee & ab luct greater trochanter, and all are lateral rota- the leg tors of the hip. Quadratus femoris is large See Fig. 53. and prominent in the cat. Not illustrated. GLUTEUS MAXIMUS The gluteus maximus in man is very large ANTERIOR THIGH and coarse and powerful since it helps maintain the erect posture of the trunk. It is ILIOPSOAS especially used in standing up from a sitting This muscle of the posterior abdominal wall position climbing stairs or hills, in deep knee is the main flexor of the hip. bends, and in running. See Figs 24, 59.

Lecture Notes Part I 35 Muscular System 4 4 RECTUS FEMORIS SARTOillUS 0: ilium The Tailor's Muscle; the I: tibial tuberosity longest muscle of the body in A: extension of tibia, humans. It is slender, strap- fIbxion of hip like (broad in the cat) and k4 See Figs 5S, 56. crosses the thigh diagon- VASTUS INTERMEDIUS ally, crossing both the hip This muscle lies deep to and the knee joints. rectus femoris. It is not 0: anterior superior iliac spine illustrated. I: proximal tibia, medial side 0: femur A: flexes thigh and knee and I; tibial tuberosity laterally rotates thigh. It can A: extension of tibia raise the leg into the "tailor's Not illustrated. position", hence it's name. See Figs. 54, 55, 60, 59. VASTUS LATERALIS 0: femur I: tibial tuberosity QUADRICEPS ?At7.11.,n. A: extension of tibia Fig. 56- Rectus FEMORIS tibial See Figs 55,58. This muscle group has Femoris four heads of origin. VASTUS MEDIAL'S All arise from the femur, Fig. 54 Sartorius 0: femur except for the rectus Right Leg I: tibial tuberosity which is from the ilium. A: extension of tibia See Figs 55, 57. All insert on the tibial tu- 4 berosity by way of a common tendon (the patellar tendon). The patella adds lev- erage to improve the angle of pull on the tibia. All extend the tibia; in addition the rectus helps flex the thigh. All are important in walking, running, climbing, junping, and kicking. The rectus is especially important in kicking. Fig. 57- Vastus Medialis Fig. 55 Anterior Thigh, Right Leg Right Leg

Lecture Notes Part I 36 Muscular System 45 4%1-1 Fig. 60. Adductor Longus & Pectineus vastus lateral's Anterior view of right thigh. GRACIUS Graceful, slender, strap- like.in humans (broad in the cat). 0: pubis Fig. 58- Vastus Lateral's & Gracilis I: proximal tibia, medial side Right Leg A: adduction of femur, braces the knee, also flexion of hip and knee See Figs. 55 and SS.

ADDUCTOR MAGNUS - si 0:pubis & ischium All are adductors I: linea aspera All originate from the pubis and/or ischium A: adduction of femur, also flexion, lateral All except gracilis insert on linea aspera. rotation, and extension of femur See Fig. 60.

ea. pectineus ADDUCTOR LONGUS \\ssi" IL.. 0:pubis adductor brevis "".%! I: linea aspera adductor longus A: adduction of femur, also flexion and lateral gluteus rotation of femur See Figs. 55, 59, 60. maximus ADDUCTORBREVIS adductor magna 0:pubis & ischium iRT I: linea aspera A: adduction of femur, also flexion and lateral Linea aspera vai rotation of femur See Fig. 60. k7i=

PECTINEUS 0:pubis I: linea aspera Fig. 59- Adductor Insertions A: adduction of femur, also flexion and lateral Posterior view of right thigh, hamstrings removed. rotation of femur See Figs. 55, 59, 60.

Lecture Notes Part I 37/4 6 Muscular System ',MAO

All originate from ischial tuberosity. All insert on the lower leg. All extend the thigh and flex the knee; they are important in walking. All rotate the leg. Fig. 62- Biceps All brace the knee. Femoris Posterior View, long head Right Leg biceps femoris

short head biceps fentoris t

.4.. Ir i.s 1,4#\) I. leire ....*11:0110.P, .....,...*w. 'r1

tree' ay

Fig. 63- Fig. 61- Hamstring insertions Senimeinbranosus Posterior View, Posterior View of Right Knee Right Leg

BICEPS FEMORIS 0: two heads of origin, long head: ischial tuberosity, 'tort head: linftaaspera of femur I: proximal fibula, lateral side ischial A: extension of hip, flexionof knee, and tuberosity lateral rotation of leg SeeFigs. 61 and 62. 1.,ele 4 SEMIMEMBRANOSUS 0: ischial tuberosity N e. I: proximal tibia, medialside 4. a'.; A: extension of hip, flexionof knee, and medial rotation of leg See Figs. 61 and 63. Fig 64- SEMITENDINOSUS 0: ischial tuberosity Semitendinosus Posterior View, I: proximal tibia, medialside Right Leg A: extension of hip, flexion ofknee, and medial rotation of leg See Figs. 61 and 64.

Lecture Notes Part I 38 47 Muscular System 41.

-,k.;c.:\-',,,`*--',.-:-.,'',.:1.:".,.-,--",-:==-='-' ..?:.....,-...-,-- -.:.z.--.;4 ;,,.:...:::',... A }.,, .1 ir i f,..,,, I ., , ,,,, ...ir .., PERONEUS TERTI

: I:

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1f r, I.0,1_1' II I I

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:L 00 : : So . 0: 00 : t II '

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* # PERONEUS BREVIS SOLEUS 0: fibula and intezosseus membrane 0: tibia and fibula I: base of the 5th metatarsal I: calcaneus A: plantar flexion and eversion of foot A: extension (plantar Figs. 66 and 67. flexion) of ankle See Fig. 69.

PLANTARIS In humans this is a small muscle with a very long tendon. 0: lateral epicondyle of femur I: calcaneus A: extension (plantar flexion) of ankle and flexion of knee See Fig. 69.

POPLITEUS Fig. 69- Saws and This small muscle is Plantaris Fig. 66- AnteriorView of Right Foot confined to the floor Right Calf Posterior View, Showing common insertion for tibialis anterior and of the popliteal fossa. peroneus longus. Gastrocnemius Removed 0: femur, lateral condyle I: tibia, medial side A: rotates lower leg medially to unlock the knee joint These are the calf muscles. Ere. See Fig. 61. Gastrocnemius,soleus, .3 1,:s and plantaris have a plantaris common tendon of insertion, the tendocalcaneus (Achilles' tendon), The tendons of this which inserts on the group pass behind the calcaneus and raises medial malleolus. They the heel. all plantar flex (extend) and invert the foot. GASTROCNEMIUS 0: two heads of origin, TIBIALIS POSTERIOR the medial and lateral epi- astrocnendus 0: tibia, fibula, and condyles of the femur interosseous membrane I: calcaneus I: tarsus $ A: flexion of knee and ex- tendocalcaneus A: plantar flexion & tension (plantar flexion) iLti inversion of foot of ankle See Figs. 70, 73, and it

See Figs. 70 and 61. 10

Fig. 68- Gastrocnemius Fig. 70- Tibialis Posterior Right Calf Posterior View Right Leg, Posterior View Lecture Notes Part I 40 4 9 Muscular System FLEXOR DIGITORUM

LONGUS t"4 0: tibia L four toes A: flexion of the toes, as well as plantar flexion & inver- membrane sion of foot See Figs. 71, 73, 74. flexor digitorum

ti Fig. 71- Flexor Digitorum Right Leg, Posterior View

FLEXOR HALWCIS LONGUS The tendon lies Fig. 74-A closest to the bone. 0: fibula great toe A: flexion of the big toe as well as plantar flexion & inversion of foot See Figs. 72, 73, and 74.

Fig. 71- Flexor Hallucis Longo Right Leg, Posterior View

.tt4 Achilles tendon "4:1: :47' tibialis "Al #a posterior .t.;". flexor .Atr.::ts's Vo digitoru medial $1..q malleolus Fig. 74-B flexor hallucis tongus Fig. 74 A & B- Insertions of the Deep Calf Muscles. Figure 74A is less detailed than Figure 748. Right Foot, Ventral V.ew Fig. 73- Tendons of Deep Calf Muscles Right Foot, Medial View Lecture Notes Part I 41 Muscular System 5 0 intermediate mass of thalamus

parieto-occipital / fissure

calcarine fissure

IVth ventricle inferior cerebellar peduncle

Fig. 76- Human Brain In Sagittal Section

Lecture Notes Part I 42 Nervous System Introduction to Nervous System Basic Terminology and BasicConcepts \k, `$

NEURONS MYELINATION cell body myelin dendrite nodes of Ranvier axon neurilemma NEUROGLIA Schwann cells Schwann cells "Jelly Roll Theory of myelin formation" oligodendroglia regeneration astroglia unmyelinated nerves; microglia OTHER COVERINGS: EPENDYMAL CELLS endoneurium perineurium M'RaM.A*21. epineunum

boutons terminaux; , synaptic vesicles; . .. synaptic cleft; Gray matter areas are regions where cell presynaptic membrane bodies and dendrites predominate. The im- post synaptic membrane; plication is that synapses are made here. Masses of gray matter are called: receptor sites cortex transmitter esterase nuclei motor end plate ganglia or by individual names such as: NEUROTRANS MITTERS. olive FACILITATORS: amygdala Acetylcholine hippocampus Adrenalin hypothalamus Epinephrine thalamus Norepinephrine NUCLEUS: A group of nerve cell bodies within the INHIBITORS: CNS; no connective tissue boundaries. Serotonin Dopamine GANGLION: GABA A group of nerve cell bodies outside the CNS; encapsulated by connective tissue. THE NERVE IMPULSE: CORTEX: A nerve impulse is a traveling membrane A surface layer of gray matter (about 114 depolarization. inch thick) found on the cerebrum and cerebellum.

Lecture Notes Part I 43 Nervous System 52 White matter areas are regions where myelin is predominante. The implication is that axons are passing thru\ough the area in large numbers. Masses of white matter are called by such names as: tracts nerves conarnissures pathways fasciculi corona radiata

TRACTS: Bundles of axons traveling within the CNS; not covered with connective tissue wrappings. ascending or afferent tracts (sensory) descending or efferent tracts (motor) Commissures

NERVES: Bundles of axons traveling outside the CNS; covered with connective tissue wrappings. Some nerves are afferent and some are efferent.

Lecture Notes Part I 44 or 3 Nervous System Spinal Cord Anatomy & Spinal Nerves

dorsal median septum

dorsal root of spinal nerve

dorsal white column (funiculus) dorsal root ganglion

dorsal ltom

dorsal white cornmissure

mixed spinal nerve central canal

ventral white conunk sure

ventral white colt= ventral root of spinal nave

ventral median sulcus

Fig. 77- Diagram of Spinal Cord in Cross Section

LATERAL HORN CELLS: ;s ;::;v''-., Lateral horn cells are the cell bodies of auto- SENSORY NERVES nomic nervous system motor neurons that DORSAL ROOT GANGLION CELLS synapse with cells in ANS ganglia. Lateral The receptor of a sensory nerve resides in horn cells are also called preganglionic the periphery of the body, the axon synapses motor neurons. (Postganglionic neurons are with a nerve cell in the gray matter of the those which start in the ganglia and synapse spinal cord, and the cell body resides outside with smooth muscle, cardiac muscle, or of the cord in the dorsal root ganglion. gland cells.)

INTERNUNCIAL NERVES SPINAL CORD TERMINOLOGY The cell body, axon, and synapse of an Cervical Enlargement; internuncial neuron all lie entirely within the Brachial Plexus; spinal cord. Lumbar Enlargement, Lumbosacral Plexus; MOTOR NERVES: Conus Medullaris; ANTERIOR HORN CELLS: Cauda Equina; Anterior horn cells are the cell bodies of Filum Terminale; motor neurons which synapses with skeletal muscle cells. Lecture Notes Part 1 45 i4 Nervous System BRACHIAL PLEXUS: C5-C8 ANDT1 Some branches from this plexus supply the muscles and skin of the shoulder There are 8 pairs of girdle. C1- C4. roots of cervical nerves, 12 pairs cervical plexus cervical There are four major of thoracic nerves, 5 pairs enlargementnerves from the brachial of lumbar nerves, and 5 plexus that supply the skin C S - Tl, roots of pairs of sacral nerves, brachial plexus and muscles of the arm. and 1pair of coccygeal They are named and dis- nerves. The roots of these tributed as follows: nerves often combine in RADIAL NERVE : complex patterns to form extensors of both arm plexuses (networks). There thoracic nerves and forearm are four important plexuses: MUSCULOCUTANEOJS NERVE : ChRVICAL PLEXUS: C1-C4 lumbar flexors of upper arm C 1-3 supply the muscles and enlargement MEDIAN NERVE : skin of theneck and shoulder. flexors of forearm, There is one major nerve thumb side from the cervical plexus Li - S3, cauda conus equina (roots of medularisULNAR NERVE : (mostly C4): lumbosacral flexors of forearm, plexus) PHREN1C NERVE little finger side supplies the diaphragm filum terminate Fig. 78- Diagram of Human Spinal Cord & Spinal Nerve Roots Longitudinal View

CI to neck C2 CN XI musclesC3

to shoulder 4muscles Cr.; phrenic nerve to brachial plexus

Fig. 79- Distribution of Cervical Plexus Left Arm, Anterior View. Fig. 80- Distribution of Brachial Plexus I. radial nerve 2. musculocutaneous nerve 3. median nerve 4. ulnar nerve

Lecture Notes Part I 46 55 THORACIC NERVES : TJ12 The thoracic nerves (except for Ti) do not form a plexus, they simply become the:

INT ERCOSTAL NERVES.

LUMBOSACRAL PLEXUS: The lumbosacral plexus is divided into two subsections, the lumbar plexus and the sacral plexus.

LUMBAR PLEXUS: I.,- L.

FEMORAL NERVE: anterior thigh muscles and skin (quadriceps, iliopsoas, and sartorius).

OBTURATOR NERVE: gracing, adductor longus, and adductor brevis

SACRAL PLEXUS:L4 eS3)

SCIATIC NERVE tibial and peroneal branches. Supplies gluteal region; adductor magnus; posterior thigh and all of leg and foot. Safe gluteal quadrant.

PUDENDAL NERVE: sensory and motor to the genitalia, pelvic organs and pelvic muscles.

Lecture Notes Part I 47 Nervous System

4.) AUTONOMIC NERVOUS SYSTEM

There are two divisions of the ANS:sympa- COLLATERAL thetic and parasympathetic. The two divi- These are sympathetic ganglia. Thereare ?ins have some things in common and they three of them: have some differences. *celiac ganglion superior mesenteric ganglion, inferior mesenteric ganglion.

TERMINAL EFFECTOR ORGANS: These are parasympathetic ganglia. Theyare One important similarity is that both divi- located within the wall of theorgan being sions supply the same effectororgans, supplied. They are very small and willnot namely smooth muscle, cardiac muscle, and be visible in the laboratory. gland. PREGANGLIONIC CELL LOCATION

GANGLIA: THORACOLUMBAR: A second similarity is that both divisionsuse For the sympathetic division thepregan- ganglia. However the ganglia havevery glionic cell body is located between sections different locations in the two divisions T1 -T12 and Ll- 11 of the spinal cord, hence the synonym thoracolumbarnervous systei- The cell body itself is knownas a Lateral MOTOR SUPPLY: Horn Cell. A third important feature shared by both CRANIOSACRAL: divisions is that motor supply to the, effector For the parasympathetic division thepregan- organ requires two motor nerves. The first of glionic cell body is located in either the these nerves is termed a preganglionic brain stem or the sacral region of the cord, neuron since it starts in the CNS and ends at hence the synonym craniosacralnervous a ganglion. The second of these nerves is system. The specific nerves involved are: termed a postganglionic neuron since it cranial nerves III, VII, IX,at,<, and spinal starts in the ganglion and goes to the effec- nerves S2-S5. tor. NEU ROTRANSMITTERS: The synaptic neurotransmitter usedat the postganglionic synapse differs for thetwo GANGLION LOCATION: systems.

PARAVERTEBRAL: ADRENAUN These are sympathetic ganglia. Thereare 22 The sympathetic systemuses adrenalin, of them on each side of the body. Theyare epinephrine, or norepinephrine as itsneuro- located next to the vertebral column, andare transmitter, hence the synonym adrenergic connected to one another in a chain like nervous system. formation, hence: paravertebral chain. The ACETYLCHOLINE term sympathetic trunk also refers to the The parasympatheticnervous system uses chain of paravertebral ganglia. acetylcholine as its neurotransmitter, hence the synonym cholinergicnervous system.

Lecture Notes Part I 48 Nervous System 57 HYPOTHALAMIC CONTROL: heart causes an increased heart rate without The sympathetic nervous system is regulated necessarily involving mass discharge to the by the posterior and lateral regions of the body in any generalized way. hypothalamus, including the area knownas the mammillaty bodies. SPECIFIC ACTIONS: The parasympathetic system is regulated by SYMPATHETIC: the anterior and medial regions of the hypo- dilates blood vessels to muscles and skin; thalamus. constricts blood vessels to viscera; increases the rate & strength of heart contractions; increases the rate and depth of respiration; dilates the pupil; tve., e term autonomic imp es regu ton and inhibits saliva flow; adjustment. inhibits digestive secretions; inhibits peristalsis; The sympathetic system generally mobilizes constricts the sphincters of bladder and and expends energy, and preserves the anus (up to a point); individual's existence. causes ejaculation followed by constriction The parasympathetic system generally of blood vessels to the erectile tissues. conserves and stores energy resources and preserves the species. PARASYMPATHETIC: constricts the blood vessels to muscles and skin ; EMERGENCY ACTION: dilates the blood vessels to viscera; In addition to its homeostatic function, the decreases heart rate; sympathetic system is also capable of a mass decreases respiration; discharge, causing large amounts of adrena- constricts the pupils; lin to be released from the adrenal medulla. stimulates flow of saliva This type of mass action causes pronounced stimulates flow of all digestive secretions; physiological changes known as the fightor stimulates peristalsis; flight syndrome. relaxes sphincters of the bladder and anus; promotes sexual arousal and dilates blood HOMEOSTASIS vessels to the erectile tissues. The dramatic effects of a mass discharge of the sympathetic nervous system in stressful situations (fight or flight syndrome changes ) 'PHYS1 NECTIO should not obscure the fact that the sympa- Re a '''' thetic nervous system also functions every day, every hour, every minute to give a tonic All preganglionic motor nerves exit from the balancing effect. CNS along with the motor root of ordinary spinal or cranial nerves. The end result achieved by the ANS is homeostatic adjustment and regulation. Both The preganglionic parasympathetic nerves divisions are operating constantly to keep simply stay with the spinal or cranial nerve the body in homeostasis and travel to their destiAation, but the preganglionic sympathetic nerves must leave For example, tonic discharges to the arte- the spinal nerves to get to the ganglion, and rioles maintain arterial blood pressure. Also, then the nerve exiting from the ganglion stimulation of the sympathetic nerves to the must rejoin the spinal nerve. Lecture Notes Part I 49 Nervous System v8 COMMUNICATING RAM SPLANCHNIC NERVES; The nerves going to and from the ganglion Preganglionic nerves found in the abdomen travel as groups called rami. The pregan- and pelvis headed for the collateral or glionic nerves are myelinated so they form a terminal ganglia (not the paravertebral while ramus communicans. The postgang- ganglia. They may be either sympathetic or lionic nerves are unmyelinated so they form parasympathetic. a gray ramus communicans.

dorsal root clonal root ganglion

1.14\44%...... '1"to effector organ lateral horn cell

gray rams communicans

white ramus communicans

.....

paravertebral ganglion

splanchnic new sympathetic trunk

collatera ganglion

to effector organ

Fig 81- Communicating Ram! and Splanchnic Nerves

Lecture Notes Pert I 50 Nervous System Cranial Nerves Cranial nerves are typically classifiedas zones, each supplied by one of the three sensory, motor, and mixed. It is not usually branches of the nigeminaL The mandibular acknowledged, but any cranial nerve which branch is the one that is bothsensory and contains a motor component will also motor, the other branches are just sensory. include sensory fibers from the stretch The sensory supply is for pain, touch, and receptors (proprioceptors) in that muscle. temperature.

A. OPHTHALMIC DIVISION: I. OLFACTORY: Sensory from theupper 113 Special sensory nerve for the sense of the face, including the of smell. The receptors are actually cornea of the eye. brain cells that begin in the mucous membrane of the nose and then B. MAXILLARY DIVISION: penetrate the cribriform plate of Sensory from the middle the skull to join the olfactory bulb zone of the face, including of the brain. This nerve is unique the maxilla and upper teeth, optic' duasm' because it is the only known and the nose area. instance in which brain cells C. MANDIBULAR DIVISION: themselves interface with the Sensory from the lower 1/3 environment. of the face, including the jaw and lower teet, and 11. OPTIC: trigentinal (V) Motor to the muscles of Special sensory nerve for (12"11 " mastication (mainly). light. The receptors are the winch) rods and cones of the retina of the eye. VI. ABDUCENS facial (V1:1) Motor supply to the auditory (VM) lateral rectus muscle, III. OCULOMOTOR: gic"WharYngeal O)) which isone ofthe six Motor nerve: hypoglossal oao vagus (X) extrinsic (voluntary) a. Motor innervation to four eye muscles. of the six extrinsic (voluntary) muscles of the eye. VII. FACIAL: b. Parasympathetic innervation to the Mixed nerve. ciliary muscles of the lens and the cir- a. Sensory for taste cular (constrictor) muscles of the iris from the anterior 2/"Z of (pupil). the tongue. Fig. 82- Cranial Nerves b. Motor to the muscles IV. TROCHLEAR: Htnnan Brain, Left Side, Inferior View of facial expression. Motor supply to the superior oblique muscle, one of six extrinsic (volun- c. Parasympathetic to tary) eye muscles. the submandibular and sublingual salivary glands, tear glands, and V. TRIGEMINAL: mucous glands of nose. Mixed nerve: 1 'le face is divided into three

Lecture Notes Part I SI Nervous System VIII. AUDITORY b. to sternocleidomastoid and trapezius (also called Vestibulo-cochlear or Auditory- muscles. vestibular, or Stato-acoustic): Sensory nerve: two separate divisions, the cochlear XII. HYPOGLOSSAL: nerve (from receptors in the cochlea of the Motor to the tongue muscles for speech and inner ear), is for hearing, and the vestibular swallowing. nerve (from receptors in the vestibule and semicircular canals of the inner ear), is for equilibrium.

IX. GLOSSOPHARYNGEAL: Mixed nerve a. Sensory for taste from the posterior 1/3 of the tongue. Also sensory from the carotid sinus for blood pressure regulation. b. Voluntary motor to the muscles of the pharynx, for swallowing. c. Parasympathetic to the parotid salivary gland.

X. VAGUS: Mixed nerve; chiefly parasympathetic. a. Parasympathetic to all internal organs in chest and abdomen. Slows the heart, constricts the airways. promotes peristalsis and promotes digestive secretions. Innervation for coughing, sneezing, and vomiting reflexes. b. Voluntary motor to pharyngeal muscles for swallowing, and to larynx muscles for speech. c.Sensory from the: a. tongue (taste), b. carotid &aortic bodies (blood press c. larynx, throat, trachea, esophagus, and internal viscera of chest and a)domen (temperature and stretch receptors).

XI. SPINAL ACCESSORY: Motor to skeletal muscles in neck area. a. to muscles of pharynx and larynx for swallowing and speech.

Lecture Notes Part 1 52 Cl Nervous System Ventricles, Spinal Fluid, Meninges, Blood Supply

itt FORAMENA OF FOURTH VENTRICLE:

Nk, VYk. 3.5K:045es, There are two lateral foramena (foramena of LATERAL VENTRICLES: Luschka) and one midline foramen (foramen Also called ventricle I and II, there is one of Magendie). The Pith Ventricle con- inside each cerebral hemisphere. nects with the subarachnoid space sct. these openings. Each is a fairly large 0609root Mep:ze.24.411. cavity with a complexanterior horn of ventricle II iftly shape, including iv '4 anterior horn, poste- ventricle Ittn*- rior horn, and lateral S horn. FORMATION: body of 1IIRD VENTRICLE: ventricle The Choroid Plexus con- A small slit-like (ex- II stantly secretes cerebral tremely narrow) spinal fluid into the ventricles. The choroid cavity in the center of t the diencephalon. 4 plexus is thought to be a combination of the NTH VENTRICLE: ilk`r inferior hornik "In cerebral specialized capillaries Lies between the of ventriclelkt,t of the ventricles inter- cerebellum and pons twined with the epen- in the hind brain. It is posterior horn ventricle dymal cells lining the continuous with the of ventricle -44 IV ventricles. The process central canal of the of formation is thought to Fig. 83- Ventricles, Superior View spinal cord. It is described be one of selective filtra- shown superimposed upon the cerebral as beingthe shape of a three tion or secretion. dimensional diamond. hemispheres anterior horn " s FUNCTION body of Cerebral spinal fluid ventricleII PASSAGE! serves as a shock ab- =. sorber (water cush- INTERVENTRICULAR FORAMENA ion or water jacket), Also called Foramen of protecting the brain Monro: connects each of and spinal cord. the lateral ventricles to th., There is some evi- IlIrd ventricle. dence that it may provide a circulation CEREBRAL AQUEDUCT : pathway for certain Also called Aqueduct inferior horn natural chemicals or of Sylvius: connects ventricle IV cerebral aqueduct hormones. ventricle III with ventricle IV; a long canal which passes length- Fig. 84- Ventricles, Lateral View wise through the shown superimposed upon the cerebral midbrain. hemispheres

Lecture Notes Part 1 53 Nervous System 6 2 CHARACTERISTICS OF CSF: effectively partitioning the cranial space into Cerebral spinal fluid is a clear, watery, straw smaller compartments. colored filtrate of blood plasma. It is sterile, FALX CEREBRI and normally it should be free from red and white blood cells. It contains small amounts FALX CEREBELU of protein, glucose, and chloride. The vol- TENTOFNUM CEREBELL1 ume ranges from 80-200 ml, the average for falx catabri adults is 100-140 ml, with 15 ml being superior sapid' inferior sagittal sinus frontal airs' found in the ventricles, the rest in the subar- sinus achnoid space. Samples of the fluid are sphenoid air sinus usually obtained for analysis by lumbar puncture.

CIRCULATION OF CSF: Cavernous sinus Cerebral spinal fluid leaves each lateral ventricle by way of the Foramen of opthahnic Monro; it leaves the IIIrd ventricle by way mai& of the Aqueduct of Sylvius; it leaves the sinus IVth ventricle by way of the foramens of 7141plimpir I Luschka and Magendie, and enters the V subarachnoid spaces. From there it enters si facial the superior sagittal sinus (vein) by way of sinus transverse the arachnoid villi. sinus external jugular vein REABSORPTION OF CSF: jugular Vein Since the CSF is being formed constantly, it must be reabsorbed constantly, otherwise the Fig. 85- Faix Cerebri and Venous intracranial pressure would rise, with serious Drainage of the Brain consequences. Reabsorption is by way of the arachnid villi into the venous superior ARACHNOID MATER: sagittal sinus. Delicate, serous, connective tissue beneath MAN,WeW the dura; it does not dip down into the sulci, but lies close to the dura all the way. The name implies it's spider web like appear- DURA MATER: ance. The following are noteworthy features The outermost sheath of tough, dense, of the arachnoid: elastic connective tissue surrounding the ARACHNOID TRABEr t1LAE brain and spinal cord. ARACHNOID V1LU (ARACHNOID GRANULATIONS) The spinal dura extends all the way down to S2. It ensheathes the whole cord and the SUBARACHNOID SPACES: cauda equina, and extends out around the Lumbar Cistern dorsal and ventral roots of the spinal nerves. Great Cistern(Cisterna Magna) There it feathers out to become the thinner Superior Cistern epineurium covering the nerve Interpeduncular Cistern Pontine Cistern The dura surrounding the brain has three extensions. Each of these is a double fold of PIA MATER: Jura that projects inward into the fissures, Thin, delicate, highly vascular, connective

Lecture Notes Part I 54 Nervous System 63 tissue that adheres to the surface of the brain Willis. and cord and dips down into all sulci. The filum terminals at the inferior end of the The vertebrals enter the skull via the fora- spinal cord is made of pia mater. men magnum. They unite on the ventral surface of the brain stem to form the single basilar artery, which then splitsto form the two posterior cerebral arteries.

) The internal carotid arteriesenter the skull via the carotid foramen and carotid canals. The blood (containing absorbed CSF) drains Each internal carotid splits intoa middle °tit of the skull by passing sequentially into cerebral artery and an anterior cerebral the transverse sinus, sigmoid sinus and artery. internal jugular vein. The two anterior cere'lrals join via the If at any time this circulation pathway is anterior communicating artery. Each middle blocked pressure will start buildingup inside cerebral artery joins with the posterior the cranium. If blockageoccurs in child- cerebral artery via the posterior communi- hood, before the sutures of the skull have cating artery. fused, the head will enlarge. This pathology is called hydrocephalus.

Common nutritive substances like glucose

kkatsisgs. , and oxygen pass freely into the brain tissue, The arteries which supply blood to the brain as well as into the CSF, but if chemicals are the paired vertebral arteries and the potentially capable of disrupting brain paired internal carotid arteries. Once inside function are introduced into the bloodstream the skull these four arteries join the Circle of they will be screened out (except Na+, K+, anterior and certain drugs). The onlyarea of the anterior puntinicating cerebral brain excepted is the posterior inferior region of the brain stem (part of the medulla oblongata), which is the location of the center that controls the vomiting reflex.

Mechanisms: The present theory is that the capillaries of the brain create the barrier, there are no pores in the capillary walls in the central nervous system, therefore substances must penetrate the capillary walls directly. Another theory is that astrocytesact as middlemen, carrying substances from the capillaries to the nerve cells. Not all substances passing through the capillaries are able to enter the astrocytes.

Fig. 86- Blcod Supply to the Brain: The Circle of Willis

Lecture Notes Part I 55 64 Nervous System Fig. 87- Human Brain, Left Hemisphere Inferior View

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RETICULAR FORMATION: In the core of the midbrain and hindbrain (running thru the white matter of the medulla, pons and cerebral Fig. 90- Sagittal Section of Adult Human Brain peduncles) is the so called showing further subdivision of the three primary regions. reticular formation, a network of neurons through which sensory pathways on the way to the cortex must pass. The reticular formation appar- ently screens information, blocking irrelevant material and passing through that which is relevant, thus helping to pre- }rhinencephalonvent information (limbic system) overload. Another function of neopallium ki the reticular formation is to alert higher :enters that a bar- rage of sensory information is soon to arrive.

Fig. 91- Human Brain, inferior View showing subdivisions of the telencephalon Lecture Notes Part I ss 67 Nervous System Adult Anatomy of the Brain superiorpedundes Connects cerebellum to midbrain. middle peduncles: MYELENCEPHALON Connects cerebellum to pons. inferior peduncles MEDULLA OBLONGATA Connects cerebellum to medulla. The medulla oblongata is the lowest and oldest part of the brain. It is directly con- ARBOILVITAQ tinuous with the spinal cord below and the The arbor vitae is a branching pattern of pons above. The pyramids of medulla are tracts with a fanciful resemblence a tree. two swellings on the anterior surface of the These tracts are simply the continuation of medulla; they contain the corticospinal the cerebellar peduncles. tracts. The corticospinal tracts physically cross from left to right and vice versa at the PONS level of the medulla. This cross over is The pons is mostly white matter because all known as the decussation of the pyramids. ascending P.nd descending neuronsmust pass through it, there is no other way for CRANIAL NERVE NUCLEI axons to travel up to higher centers or down Cranialnerves IX, X, XI, XII are attached to lower centers. to the medulla, therefore we can say that the medulla regulates: respiration, heart beat, CRAWL NERD NIICLE; blood pressure (vasoconstriction), sleep, Cranial nerves V, VI, VII, VIII areattached consciousness, and reflex functions such as to the pons in an area called the olive. swallowing, vomiting, sweating, and gastric secretion. filETENcEPHALON CEREBRAL PEDUNCLES All ascending and descendingneurons must CEREBELLUM pass through the white matter of the cerebral CEREBELLAINORTEX; peduncles of the midbrain, there isno other The cerebellar cortex is the gray matteron way to go up to higher centers or down to the surface of the cerebellum. It contains the cell bodies of nerves that control muscle lower centers. Two examples of such pathways are the corticospinal (voluntary motor) coordination, muscle tone, posture, equilib- and spinothalamic (sensory) tracts. rium, and muscle memory (habit formation). PEP NUCLEUS; The cerebellum receives sensory input The red nucleus is a mass of gray matter (cues) related to the above: i.e. proprio- where axons from the cerebral cortexsyn- ception from muscles, tendons, and joints; apse with axons going to the cerebellum via visual cues, auditory cues, vestibular organ the superior cerebellar peduncles. cues, and touch cues. CRANIAL, NUCLEIC CEREBELLAR PEDUNCLEt Cranial nerves III, IV, and l st division of The cerebellar peduncles are white matter Vth are attached to the cerebral peduncles. tracts that connect the cerebellar cortex with other parts of the brain which are above CORPORA QUADRIGEMINA below and across the street from the cereJel- The corpora quadrigemina are four bodies lum. Lecture Notes Part I 59 68 Nervous System (two pairs) of gray matter in the midhrain. MEDIAL GENCULATE BODIES; Connections for cranial nerve VIII. Fibers There is a pair of superior colliculi and a arrive here from the Vestibular and Cochlear pair of inferior colliculi. nuclei of the brain stem (pons). From here UPERIOR COLLICULI; fibers are sent to the auditory cortex for These nuclei control visual reflexes such as: hearing, or to the inferior colliculus for blinking, accommodation, pupillary con- auditory reflexes. striction and dilation. They also control balance reflexes related to visual cues. The EPITHALAMUS (PINEAL BODY): optic nerves go first to the lateral geniculate The pineal body is tentatively implicated as bodies of the thalamus, and then some of the a biological clock mechanism, especially as axons continue on to the superior colliculi. concerns the onset of puberty, perhaps The two superior colliculi are connected converting circadian dark/light cycles into with one another via a band of axons called endocrine cycles. the posterior commissure.

INFERIOR COLUCUU; HYPOTHALAMUS: These paired nuclei control auditory reflexes Control centers (nuclei) for: such as the tensor tympani and stapedius body temperature reflexes. They also control balance reflexes control of anterior pituitary gla.'d via related to vestibular cues. The vestibular production of releasing factors nerves go first to the medial geniculate production of posterior pituitary bodies of the 0- **Ins, and then some of the hormones (ADH and Oxytocin) axons contito tthe inferior colliculi. sleep/wake cycles libido (sex drive) hunger thirst regulation of autonomic nervous system 3. regulation of emotional behavior via plENCEPHALAN limbic system connections to mammillary body nuclei). THALAMUS: All afferent (sensory) fibers (except olfac- TELEN_CcPHALON tion) synapse in the thalamus before being relayed to the cortex. The thalamus provides RHINENCEPHALON (LIMBIC SYSTEM) the lowest level of sensory discrimination The rhinencephalon or "nose brain" is some- (pleasant vs unpleasant, touch vs pain, times called the archipallium, indicating the temperature vs pain), but the sensation is fact that it is the oldest part of the telenceph- unlocalizedunless the relay continues to the alon. cerebral cortex. WHITE MATTER; 1,ATE6AL GENICULATE BODIES; olfactory nerves, tracts &striae These nuclei are the relay stations for the These extend from the olfactory bulbs optic nerve axons. From here messages are leading to the uncus, anterior perforate relayed to the occipital lobe of the cortex for substance,amygdala, hippocampus and image formation or to the superior colliculus cingulate gyrus. for visual reflexes, or to the pineal gland for biological clock functions. This latter con- fornix necti,A is still considered speculative. Connects amygdala and hippocampus of the limbic system to the mammillary bodies of

Lecture Notes Part I 60 Nervous System C9 hypothalamus and to the brain stem, allow- lateral fissurr ing the limbic system to influence the This fissure is also knownas the Sylvian autonomic nervous system and emotional fissure. It separates the temporal lobe from behavior. the frontal lobe. anterior commissure parieto-occipltal Assure Found at the proximal end of the olfactory This fissure can be seen from the midsagittal nerves. Connects the olfactory tracts to each view only. It marks the boundary between other. the parietal lobe and the occipital lobe. calcarine fissure COLIEWLEACEEXASSMAIMEAS451 This fissure can also beseen only from the olfactory bulbs midsagittal It starts at the occipital pole and anterior perforate substance runs forward at right angles to the parit...)- Also called the olfactory trigone since it is occipital fissure. a triangular area between the olfactory tracts collateral fissure and olfactory striae. The collateral fissure runs lengthwiseon the uncus inferior surface of temporal lobe. The uncus is the smooth anterior end of the cingulate sukus collateral gyms. The cingulate sulcus is above the cingulate hippocampus gyrus, which is above the corpus callosum. The hippocampus is a part of the collateral transverse fissure gyrus which is coiled like the tail of a The transverse fissure separates the cerebel- seahorse. lum from the occipital pole. cingulate gyrus lobes: This gyrus is above the corpus callosum and frontal parietal parallel to it. occipital temporal XLCLE1; insula amygdala The amygdala is an almond shaped nucleus CORTICAL PROJECTION AREAS: deep in the center of each temporal lobe. These are thet. learly localized sensory and motor areas also known as primary cork NEOPALLIUM: precentral gyrus: The neopallium is approximately 7/8 by ThiF gyrus of the frontal lobe is the primary weight of the human brain. motor cortex =EL postcentral gyrus: sulci and fissures: This parietal lobe gyrus is the primary midsagittal fissure sensory cortex This fissure is also known as the median walls of calcarine fissure : longitudinal fissure. It divides the cerebral cortex into two hemispheres. This cortex of the occipital lobe is the primary visual cortex. central fissure This fi ;sure is also known as the fissure or motor speech area: Rolando. It marks the boundary between the The motor speech area is in the dominant frontal lobe and the parietal lobe. hemisphere; it is the part of the frontal lobe which is just above Sylvian fissure and just

Lecture Notes Part I Nervous System 17 o anterior to the precentral gyrus. This area is overshoot their target. Rigidity and tremor also known as Brocca's area are characteristic of malfunction of the basal hearing projection area: ganglia. A band of white matter (the inter- The primary hearing cortex is located on the nal capsule) runs between the caudate superior gyrus of the temporal lobe. nucleus and the lentiform nucleus giving them a characteristic strippedappearance, COFJTJCAL ASSOCIATION AREAS; giving rise to the term corpora striata (basal The association areas are the areas of cortex ganglia + the internal capsule). are also known as secondary cortex. They caudate nucleus immediately surrounding the primary projection area. These are the areas where lentiform nucleus memories and thoughts associated with globus pallidus putamen primary events are stored. substantia nigra visual association area This is the area of the occipital lobe sur- NtifELMAZEIL internal capsule rounding the calcarine fissure. The internal capsule is a tightly bundled hearing association area group of axons traveling vertically between This is most of the temporal lobe immedi- brain stem and cortex. The bundle passes ately surrounding the primary hearing cortex through the middle of the basal ganglia and sensory association area continues upwards as the corona radiata. See next listing. This is the part of the parietal lobe immediately posterior to the primary general sen- corona radiata sory cortex. Much of the white matter beneath thecere- language association area bral cortex is the corona radiata. When the This is the area of the dominant hemisphere ascending axons in the internal capsule where the temporal, occipital and parietal escape the confines of the basal ganglia the axons spread (radiate) out to reach their lobes meet. Also known as Wernicke'sarea. designated area of the cortex. The same insula: concept in reverse applies to the descending The insula is a hidden island of cortex in the axons which after leaving the cortex must walls of the Sylvian fissure of the temporal funnel into the brain stem. lobe. This is the speech association area. corpus callosum prefrontal cortex: This very large band of axons is the brain's The prefrontal cortex is all of the frontal largest commissure; it allows the hemi- lobe anterior to the motor cortex. The spheres to share information. Without this prefrontal lobe is poorly understood, but is commissure therewould be essentially two associated with such things as "intelli- brains rather than one, and each brain would gence", reasoning ability, emotional control, be in control of the opposite side of the long range planning, personality, and moti- body. Only the dominant side (left side for vation. most people) would have access to language. THE BASAL "GANOLIA" The basal ganglia, or basal nuclei are important for the dampening and inhibiting of voluntary motor impulses so that muscles are not overactive, and movements do not

Lecture Notes Part I 62 Nervous System 71 Major Pathways of the Brain

This is the pathway for pain and tempera- This is the pathway for voluntary motor ture sensations traveling from skin to impulses traveling from the motorcortex of thalamus to sensory cortex. The decussation the brain down through the brain stem and (cross over) is at the spinal cord level so into the spinal cord, where theysynapse on that sensations coming from one side of the the anterior horn cells of the spinal cord. body immediately cross to the other side of The decussation is at the level of theme- the cord and then travel upward towards the dulla (decussation of the pyramids), and in brain. See Fig. 92. fact the swellings known as the pyramids of the medulla are in reality these corticospinal tracts.

This is the pathway for light touch and pressure sensations traveling from skin to thalamus to sensory cortex. Again, the decussation is at the spinal cord level so that sensations coming from one side of the body immediately cross to the other side of the cord and then travel upward towards brain. See Fig. 92.

This is the pathway for proprioception, stereognosis, tactile discrimination and some pressure sensations raveling from skin to thalamus to sensory cortex. The decussation is at the level of the medulla, which means that sensations coming from one side of the body travel upward on that same side of the cord until they reach the medulla, at which point they cross over and travel upward on the opposite side of the brain stem (medulla, pons, cerebral peduncles) towards the thalamus and cortex.

Lecture Notes Part I 63 Nervous System System nucleus capsule spino- neurons, Nervous ventricle temperature cord. nucleus third thalamus lentiform internal touch ventral three ventricle and spinal callostun caudate pain The lateral funiculus funiculus Tracts requires ofthe corpus lateral ventral level peduncles temperature. pathway 73 each the cerebral and sideat Spinothalamic forpain that Ventral Notice theopposite 64 and pathwaythe lighttouch. to Lateral istract for crosses Fig.92- thepathway eachpathway Section Brain Cord sp'iothalamic istract that Section lateral and IPart The thalamic Notes insula Human Cross Spinal Coronal Lecture General Sensory Receptors

when the level of stimulus is unchanging. Mostly we respond to change and tendto disregard a steady state. The exception to TRANSDUCERS: this is that pain and tendon stretchreceptors Sense receptors are transducers; they change do not adapt. one form of energy (e.g. heat, sound waves, pressure) into another form of energy (into REFERRED PAIN: electrical signals for example). Biological Pain that actually originates in a visceral transducers change one form of energy (e.g. origin may feel as though it is coming from light, heat, sound waves, pressure) into somewhere else. The explanation for this is nerve impulses, which are actually electro- probably as follows: the visceroceptor chemical signals acting on cell membranes. neuron is traveling in a mixed spinal nerve along with a peripheral sensory neuron. ADEQUATE STIMULUS: Both neurons probably activate thesame Each receptor has it's specific "adequate internuncial neuron in the centralnervous stimulus", i.e. the energy form which nor- system. Since stimulation of sensory re..zp- mally excites it. Usually there is no cross tors in the viscera is relatively uncommon over stimulation unless the stimulus is very the brain assumes that the signal is coming intense (e.g. very intense sound is painful). from the peripheral sensoryneuron, and thus ADAPTATION: misinterprets the source or origin of the Most receptors adapt in the presence of a sensation. For example: in angina pectoris, constant level of stimulus. What actually the source of the pain is in the heart muscle, happens is that they send fewer nerve im- but tilt, pain is commonly experienced to be pulses, (i.e. they "fire" at a slower rate) in the left chest, shoulder, andarm area.

'CATALOG..OFSENS..

TOUCH: Meissner's corpuscles in hairless skin Tactile discs (Merkel's discs) Hair root plexuses

PRESSURE: Pacinian corpuscles

PAIN: Free nerve endings in skin, connective tissue, and cornea.

COLD: Krause's end bulbs (corpuscles)

HEAT: Ruffini's brushes (corpuscles)

PROPRIOCEPTION: Neuromuscular spindles (stretch receptors), are found in all muscles and joints. They give constant information to the brain regarding muscle and joint positi'n and movement. Lecture Notes Part I 65 74 Nervous System TENDON LOAD: Golgi tendon organs (stretch receptors in the tendons). If a tendon is stretched to the breaking point the muscle will suddenly relax and the joint will col-lapse, preventing injuryto the tendon and muscle. (clasp knife reflex)

EXTENSOR STRETCH REFLEX: Neuromuscular spindles (stretch receptors) found in the muscles of the feet will,when stretched, cause increased contraction of the extensor muscles in the legs. This reflex is activated when the soles of the feet are pressed against the floor, causing the leg extensors to hold the individual upright,

Utricle and Saccule of the innerear give in- GRAVITY: formation to the brain that allows the bodyto orient to gravity (ability to know up from down); recognition of head position.

ACCELERATION/ DECELERATION: Semicircular canals of the innerear.

SOUND: Cochlea &organ of Cord of the innerear.

SIGHT: Retina, rods and cones

TASTE: Taste buds in papillae of the tongue forsweet, sour, salty and bitter, Other flavors area combination of taste and olfaction

SMELL: Chemoreceptors in mucosa of upper nasal cavity

BLOOD PRESSURE: Stretch receptors in aortic arch, carotid sinuses, and in superior and inferior venaecavae. Impulses from these receptors are carried by the glossopharyngeal nerves.

BLOOD CO7 : Chemoreceptors found in the aortic body and carotid bodies are sensitive to acid levels (CO2 dissolved in water creates carbonic acid); increased CO2 levels causes faster breathing.

BLOOD SALINITY: Osmotic receptors in hypothalamus

BLOOD GLUCOSE: Glucostat receptors in hypothalamus (?)

VISCERAL SENSATIONS: Very few sense receptors exist in the viscera, touch sensibility is virtually nonexistent,warmth and cold sensibility is almost nonexistent.The few receptors that exist an called interoceptors or visceroceptors. They respond to pain and distension (internal stretch) of the vis,..era.

Lecture Notes Part 1 66 5 Nervous System THE EYE vi,,:k.!,X.X.71S.,,I,Zk..:,,,::::Ni;::::,,k4SNIZ.,..X..,,grf,..',14::. ac pigment protectse retinatina by Nt tA le b.,KT: ttt,,tip ! sZ"k k ,:..,); soe. to it --i..,,,t 1.sk :.;.1. ,. t.,... absorbing excess light. The eye has three basic layers and four basic IRIS: functions. The iris is the forward extension of choroid THREE BASIC LAYERS: layer. It contains less pigment than the choroid. Different eye colors in different OUTER LAYER people are the result of varying amounts of The outer layer of the eye includes the sclera the pigment melanin in the iris. and the cornea. PUPIL: MIDDLE LAYER: The pupil is a hole in the center of the Iris. The middle layer of the eye includes the The size of the hole will change depending choroid layer, the iris, and the ciliary body. on the brightness of the ambient light.

INNER LAYER: MUSCLES OF THE IRIS The inner layer of the eye consists of the (pupil size regulation) retina. Circular Layer FOUR BASIC FUNCTIONS: Contraction of the circular muscles of the The sclera and cornea protect the retina. iris will dilate the pupil. The iris and choroid layer regulate the Radial Layer amount of light that hits the retina. Contraction of the radial muscles of the iris will constrict the pupil. The cornea, lens, and ciliary body focus the light on the retina. CILIARY BODY AND LENS The retina transduces the light stimulus Adjustment of the ciliary body will change by changing it into nerve impulses. the shape of the lens which in turn will change the focal length of the lens. This ...... process is called the "accommodation reflex".

SCLERA ELASTIC LENS In order to be transparent the lens has no The sclera is very tough thick white connec- blood vessels and no nerves, and its cells tive tissue; its function is to protect the have lost all their internal structures (during retina. embryological development), leaving them CORNEA: unable to replicate or to produce their own The cornea is the transparent front portion of energy, and yet the lens continues to grow as the sclera. In addition to protecting the retina the body grows. it is also does most of the focusing. The lens has the most concentrated protein content of any tissue in the body. As much as 60% of the lens is made of a special class of proteins called crystallins. These special CHOROID proteins perform a dual function: The choroid layer of the eye is black due to its massive amounts of melanin pigment. a. they act as structural proteins dense

Lecture Notes Part I 6' Nervous System enough to bend light efficiently bleached pigment will become purple again when protected from the light. b. they act as enzymes capable of converting sugars into energy to keep the CONES cells of the lens alive. The cones are for color vision and acute wistow & Piatigorsky, Science, June 19, 1987 vision. They contain a variety of visual pigments that are sensitive to all the differ- SUSPENSORY LIGAMENTS ent lengths of light waves in the visual These are very delicate crystal clear strands. spectrum. One end attaches to the circumference of the lens, the other end of each ligament is MACULA LUTEA White spot at rear of the eyeball where the attaches to a ciliary muscle. retina is thicker. CILIARY MUSCLES The ciliary muscles are used in the visual FOVEA CENTRALS A pit in the center of the macula lutea. This reflex known as accommodation, as in the is the area of most acute vision the to a high phrase accommodation for near vision. They concentration of cones and the absence of are smooth muscle, and they work by adjust rods in this area. the shape of the elastic lens from the resting flattened position needed for distance vision, BIPOLAR CELL LAYER to a rounder shape which is needed for near Very short neurons. Anterior to the rods and vision. cones. These neurons are stimulated by the chemical changes in the rods and cones. Contraction of the ciliary muscles will They in turn synapse with the optic nerve reduce tension on the suspensory ligaments cells. thus allowing the elastic lens to fatten This is the shape needed for focusing on close OPTIC NERVE FIBERS objects. These cells synapse with, and lie anterior to, the bipolar neurons. Light must pass through Relaxation of the ciliary muscles will a tangle of optic nerve fibers and the bipolar ir -Tease tension on the suspensory liga- layer of cells before it can strike the rods ments, stretching the elastic lens into a and cones of the retina. The optic nerve flatter shape. This is the shape needed for axons converge on the optic disk at the back focusing on distant objects. of the eye.

OPTIC DISK The optic disk is the area at the posterior pole of the eyeball where the optic nerves RETINA exit the eyeball to continue their journey to RODS the brain. Since there is no retina at this The rods are receptors for night vision, they location, the optic disk causes a " blind contain the visual pigment rhodopsin. spot" in each eye. As long as a person has Rhodopsin is purple in the dark (visual two eyes no dysfunction is caused because purple); low intensity light causes a chemi- when light is striking the blind spot in one cal reaction in the rhodopsin which in turn eye it simultaneously falls on active retina in initiates a nerve impulse. The color red is the other eye. not visible at night because rhodopsin is not sensitive to light waves in the red range. EXTRINSIC EYE MUSCLES: When exposed to bright light, rhodopsin These are the muscles attached to the out- bleaches to white and nerve impulse cease. side surface of the eyeball and used for The bleaching reaction is reversible; the moving the eye in the direction of sight. Lecture Notes Part I 68 77 Nervous System They are all voluntary (skeletal) muscleas in focus when the light waves hit the retina. opposed to the intrinsic muscles of theeye ASTIGMATISM (ciliary muscles and two iris muscles) which Congenital difficulty in focusing dueto are all smooth muscle. variable thicknesses (waviness) of the SUPERIOR RECTUS cornea and/or lens.

LATERAL RECTUS CATARACTS for abduction of the eye Opacity of the cornea or lens. Numerous MEDIAL RECTUS causes. Frequently associated with the aging process. INFERIOR RECTUS DETACHED RETINA SUPERVI OBLIQUE The retina is held smoothly in place against it runs through the trochlea the sclera by the vitreous humor. If the INFERIOR OBLIQUE retina falls away from the sclera light will not focus on it and sight is lost in that area.

IVIENT GLAUCOMA

LACRIMAL GLAND Aqueous 'humor must drain out of theeye at the same rate at which it is produced, other- VITREOUS HUMOR wise pressure will build up VITREOUS CHAMBER CONJUNCTIVMS AQUEOUS HUMOR This fluid is constantly secreted by the EXOPHTHALMIA epithelium of the ciliary body.

ANTERIOR CHAMBER POSTERIOR CHAMBER

CANAL OF SCHLEMM

CONJUNCTIVA

FAT PAD

VISUAL DEFECTS:

PRESBYOPIA The farsightedness of aging; caused by loss of elasticity in the lens. MYOPIA Congenital nearsightedness; caused by an eyeball which is too long from front to back, resulting in a focal point which falls short of (in front of) the retina. The image is thus out of focus again when the light waves reach the retina.

HYPEROPIA (HYPERMETROPIA) Congenital farsightedness; caused by an eyeball which is too short from front to back, resulting in a foca point which falls behind the retina. The image is thus not yet

Lecture Notes Part I 69 Nervous System 8 THE EAR

The features of the external ear that are of SEMICIRCULAR CANALS interest include the pins, the helix, the The semicircular canals function for "dy- lobule, the external auditory canal, and the namic" equilibrium, i.e. acceleration- decel- ceruminous glands. eration. Bony semicircular canals Semicircular ducts Ampullae TYMPANIC MEMBRANE Endolymph EAR OSSICLES: Malleus ORGAN OF HEARING (COCHLEA) Incus Stapes MODIOLUS COCHLEAR DUCT WINDOWS: Round SCALA VESTIBUU Oval VestibularMembrane SCALA TYMPANI MUSCLES: Basilar Membrane Tensor Tympani ORGAN OFCORTI: Stapedius Tectorial Membrane

EUSTACHIAN TUBE COCHLEAR FUNCTIONS Also known as the pharyngotympanic canal. LOUDNESS RESPONSE Modifications of amplitude.

PITCH RESPONSE BASIC CONSTRUCTION Modifications of frequency. Bony Labyrinth Membranous Labyrinth Endo lymph Peri lymph Hair Cells ORGANS OF EQUILIBRIUM

VESTIBULE The vestibule functions for stationary equilibrium, i.e.the sense of gravity and head position. Bony Vestibule Utricle Saccule Lecture Notes Part I Nervous System