THE MUSCULOSKELETAL SYSTEM THE TOPICS IN MUSCULOSKELETA SYSTEM a. Skeletal Tissue b. Articulations (Joints)-Arthrology. c. Axial Skeleton d. Appendicular Skeleton e. body muscles SKELETAL TISSUES LEARNING OUTCOMES At the end of this lesson, you should be able to: 1. Describe the structural organization of bone 2. Describe the functions of the skeleton 3. Classify and describe characteristics of skeletal tissue 4. Classify and describe characteristics of bone
The skeleton serves as a support or framework of the human body. It is a combination of bones joined together. The two major type of tissue found in the skeletal system are bone and cartilage connective tissue
FUNCTIONS OF THE HUMAN SKELETON a. Body Support. The skeletal system provides a framework for the human body, contribute to shape, alignment, and positioning of the body parts b. Protection. Bony boxes protects the delicate structures they enclose. E.g. skull, pelvis, thoracic cavity, vertebral column
c. Motion. Bones with their joints constitute levers that move as muscles contract d. Mineral Storage. Bones are the major reservoir for calcium, phosphorus and other minerals e. Formation of Blood Cells (Haemopoiesis). Blood cell formation is carried out by myeloid tissue found in the bone marrow - mainly found in flat bones.
BASIC STRUCTURE OF AN INDIVIDUAL BONE The skeleton is made up of 206 individual bones joined together by ligaments. Each bone is an organ made up of various body tissues. Bones can be classified according to structure or shape. According to structure, they are classified into: (1) Compact or Lamella bone or cortical bone - cortex (2) Cancellous or Spongy or woven bone - medulla
Individual bones are composed 2 parts: - 1. Cortex - The cortex is the outer layer of the individual bone made up of compact bone 2. Medulla. The medulla is the central portion of the individual bone made up of cancellous bone.
Bone marrow There are two types of bone marrow: - 1. Yellow bone marrow - mostly made up of yellow fat tissue. 2. Red bone marrow – made up of haemopoetic tissue which is the only site in adults for the formation of red blood cells (haemopoiesis).
TYPES OF BONE Individual bones of the skeleton can be classified into 4 major types depending on their shape. These are: 1. Long bones 2. Short bones 3. Flat bones 4. Irregular bones
a. Long Bones. The basic structure of a long bone is made up of 5 major parts e.g. femur. b. Short Bones. The short bones, such as those of the wrist and feet, have a thin layer of compact bone surrounding an inner mass of spongy bone. Example: carpal bones.
c.Flat Bones. The flat bones are constructed with two plates of compact bone, which enclose between them a layer of spongy bone. The spongy bone is richly supplied with blood vessels and red marrow. Example: the cranial frontal bone. d. Irregular Bones. The irregular bones are those that do not fit into the three categories above. Example: a vertebra SHORT BONES –HAND FLAT BONES -HUMAN SKULL IRREGULAR BONES –VERTEBRAL COLUMN LONG BONES-HUMERUS
Sesamoid Bones Sesamoid bones are small masses of bone that develop in tendons at points where great forces are applied to the tendons. The most obvious and largest sesamoid bone is the patella, or kneecap.
Blood Supply of an Individual Bone. • A system of blood vessels enters and spreads out through the periosteum. • Additional blood vessels, called "nutrient vessels," penetrate the cortex of the bone and spread out through the marrow. • The passageways for penetration of these vessels are called the nutrient canals.
Osteogenesis Osteogenesis is the process of development of bone from small cartilage or membranous models to adult bone
DISEASES AFFECTING THE SKELETAL TISSUE •Malignant tumors (cancers)- Osteosarcoma, Chodrosarcoma •Metabolic diseases – Osteoporosis, Rickets, Osteomalacia, Paget’s disease (osteitis deformans) •Infections – Osteomyelitis.
THE AXIAL SKELETON The human skeleton is a collection of individual bones articulated (joined) together. (206 individual bones in total) The major subdivisions of the skeleton are 1.The axial skeleton – 80 bones 2. The appendicular skeleton – 126 bones
It is the central framework of the human body, and its composed of the following 3 components: - 1.The skull 2.The vertebral column (spine) 3.The thoracic cage (rib cage)
The axial skeleton consists of 80 bones: •29 bones in the head - 8 cranial and 14 facial bones and 7 associated bones (6 auditory ossicles and the Hyoid Bone) •25 bones of the thorax - (the sternum and 24 ribs) •26 bones in the vertebral column (24 vertebrae, the sacrum and the coccyx)
THE SKULL The skull is the bony framework (skeleton) of the head region. It has two major subdivisions: the cranium which encases and protects the brain and the facial skeleton which is involved with the beginnings of the digestive and respiratory systems.
Cranium, 8 bones 1 Occipital. 2 Parietals. 1 Frontal. 2 Temporals. 1 Sphenoidal. 1 Ethmoidal.
In addition, there are 3 pairs of ear ossicles (6 total): –Malleous –Incus –Staples
THE VERTEBRAL COLUMN(SPINE) The vertebral column, or spine, is made up of a vertical series of bony blocks called vertebrae. These vertebrae are joined together in such a way as to form a semiflexible rod. The spine is the central support for the trunk, yet allows trunk movements. DIVISIONS OF THE VERTEBRAL COLUMN
The vertebral column has 32-33 vertebrae, one on top of the other. These vertebrae are arranged in regions. The vertebrae of each region have a characteristic shape. The regions are as follows:
Cervical (neck) region, with 7 cervical vertebrae. (b) Thoracic (chest) region, with 12 thoracic vertebrae. (c) Lumbar (low back) region with 5 lumbar vertebrae. (d) The sacrum, which is a bony fusion of 5 sacral vertebrae. (e) The coccyx ("tail"), with 3-4 coccygeal vertebrae together.
The Thoracic (Rib) Cage The rib cage forms a protective enclosure for the vital organs contained within the thorax (chest) such as the heart and lungs. It also allows the movements of breathing to take place.
The Rib Cage The rib cage consists of the 12 thoracic vertebrae, 12 pairs of ribs, and the sternum. Each rib is curved laterally from back to front. All 12 pairs of ribs are attached posteriorly to the thoracic vertebrae. The upper seven pairs of ribs (true ribs) are attached directly to the sternum by their costal cartilages.
The eighth through tenth pairs of ribs (false ribs) are attached indirectly to the sternum through their costal cartilages (by attaching to the costal cartilage of the rib above). Rib pairs 11 and 12 (floating ribs) do not attach to the sternum. Instead, they are embedded in the trunk wall muscles.
The Ribs There are 3 types of ribs: True Ribs – ribs 1-7 ; these are attached directly to the sternum through their own costal cartilages. False Ribs – ribs 8-10; their costal cartilages are joined to the rib just above them so their attachment to the sternum is indirect Floating Ribs – ribs 11-12; these ribs attach to vertebrae, but not to the sternum so they float on one end
THE APPENDICULAR SYSTEM Appendicular skeleton refers to the bones of the limbs and the girdles that attach them to the axial skeleton. It is made up of the skeletal elements of the upper and lower members. These members are appended (attached) to the axial skeleton. The appendicular skeleton is made up of a total of 126 bones plus 8 sesamoid bones
Functions of the appendicular skeleton 1.Locomotion 2.Protection of major organs of digestive, excretion and reproductive organs 3.Holds and supports the limbs 4.Enables skilled movements of the hands
Structural Organization of the appendicular skeleton •The appendicular skeleton is generally organized into upper and lower limbs. •Each limb is made up of the following 4 segments: - 1.Girdle 2.Proximal segment 3.Middle segment 4.Distal segment
Carpal Bones – Mnemonic- She Looks Too Pretty Try To Catch Her S: scaphoid L: lunate T: triquetrum P: pisiform T: trapezium T: trapezoid C: capitate H: hamate
The Circus Needs More Interesting Little Clowns. T: Talus C: Calcaneus N: Navicular M: Medial cuneiform I: Intermediate cuneiform L: Lateral cuneiform C: Cuboid MUSCLE TISSUE
At the end of this lesson, you should be able to: 1.Classify and describe Muscle tissue 2.Describe the structure of skeletal muscle 3.Categorize and describe the muscle organ 4.Describe nomenclature of muscles 5.Describe general arrangement of muscles
MUSCLE TISSUES The cellular elements of muscle tissues are specialized to produce motion by contraction. They also produce body heat. a. Smooth muscle tissue is utilized to make up the muscular portion of the various visceral organs b. Cardiac muscle tissue makes up the muscular wall of the heart--the myocardium. c. Striated muscle tissue is used in the makeup of several types of muscles. The main type of muscle is the skeletal muscle. Other types of muscles made with striated muscle tissue are the facial or integumentary muscles and muscles of the jaw apparatus.
THE SKELETAL MUSCLE •There are 600 named muscles in a human body •Each skeletal muscle is an individual organ of the human body. •Each is made up of several types of tissues-- mainly, striated muscle fibers and FCT (fibrous connective tissue). •Each is attached to and moves bones. •Bones are parts of the skeleton serving as levers.
General Construction of a Skeletal Muscle •The large portion of a muscle is known as its belly or fleshy belly. •This muscle is attached to bones by tendons or aponeuroses. •Tendons and aponeuroses are similar to each other. However, tendons are cord-like and aponeuroses are broad and flat. •The fleshy portion may be directly connected to the bone. If so, it is called a "fleshy attachment."
Structure of a muscle organ Connective tissue coverings –Endomysium – covering muscle fibers –Perimysium – Covering muscle fascicle –Epimysium – Covering the whole muscle Tendon – cylindrical, tough, Cord-like structures attaching muscles to the bone Apponeurosis – Broad, flat sheet of connective tissue attaching some of the muscles to the bone. Tendons and apponeurosis are continuous with the fibrous coverings of muscles
Size, Shape, and Fiber Arrangement Skeletal muscles are organs They vary in size, shape and arrangement of fibers Six muscle shapes are used to describe and categorize skeletal muscles. These are: -
Parallel muscles eg sartorius, rectus abdominis Convergent muscles eg pectoralis major Pennate (feather-like) muscles – unipennate, bipennate, multipennate muscles eg flexor pollicis longus, Rectus femoris and deltoid muscles respectively Fusiform muscles eg brachioradialis Spiral muscles eg latissimus dorsi Circular (sphincter) muscles eg orbicularis oris
Attachment of Muscles Most muscles span over at least one joint They are attached to both articulating bones When contraction occurs, one bone is fixed while the other moves Points of attachments are called origin and insertion Origin is the point of attachment that does not move while insertion is the point of attachment that moves when the muscle contracts
Muscle actions •Skeletal muscles almost always act in groups •This leads to functional classification of muscles or muscle groups •Several terms used to describe muscle actions include –Agonists (prime mover) – directly perform specific movements – action or function of the muscle –Antagonists – directly oppose agonists –Synergists – contract at the same time as agonists –Fixators – function as joint stabilizers
Muscular Neurovascular Bundle (NAVL) (1) From the main NAVL (nerve, artery, vein, lymphatic), there are branches going to each muscle. These muscular branches are bound together by an FCT sheath to form a neurovascular bundle. (2) A motor point is a specific location on the surface of the muscle where the neurovascular bundle enters. (3) A motor unit is a single motor neuron and the number of striated muscle fibers activated by it (innervation). The importance of the motor unit is that its fibers work in unison. Either all fibers within a unit contract or none contract. When a certain amount of force is needed, one unit after another is recruited until just enough units are available to produce the desired action.
NAMING SKELETAL MUSCLES The name of a muscle may appear with the abbreviation M., meaning Musculus or muscle. We abbreviate muscles (plural) with the symbol Mm. Skeletal muscles are named according to their physical attributes (shape, size, length, etc.), their location, direction of fibers, number of heads or divisions, points of attachments, or their function.
EXAMPLES SHAPE: •deltoid M. DELTA = D , Greek letter D •biceps M. BICEPS = two-head BI = two CEPS = head
SIZE: •adductor magnus M. MAGNUS = great, large
LENGTH: adductor longus M. LONGUS = long
LOCATION: biceps brachii M. BRACHII = of the arm biceps femoris M. FEMORIS = of the thigh
FUNCTION: rotatores Mm. ROTATORES = rotators (They turn/rotate the vertebral column.)
ARRANGEMENT OF HUMAN SKELETAL MUSCLES
Trunk Musculature The trunk musculature is arranged in two ways: •longitudinal muscles •oblique muscles
Together, they: - (1) Maintain trunk posture. (2) Move the parts of the trunk. (3) Adjust the internal pressures of the trunk to perform certain functions such as breathing Joints A joint or articulation (or articular surface) is the location at which bones connect. They are constructed to allow movement (except for skull, sacral, sternal, and pelvic bones) and provide mechanical support, and are classified structurally and functionally. Structural classification (binding tissue) Structural classification names and divides joints according to the type of binding tissue that connects the bones to each other. There are three structural classifications of joints:
There are three structural classifications of joints: fibrous joint – joined by dense regular connective tissue that is rich in collagen fibers cartilaginous joint – joined by cartilage synovial joint – not directly joined – the bones have a synovial cavity and are united by the dense irregular connective tissue that forms the articular capsule that is normally associated with accessory ligaments.
Functional classification Functional classification is based on the degree to which the joint permits movement. There are three types: A synarthrosis joint permits no movement. Structurally, it may be a fibrous or cartilaginous joint,are fixed joints eg skull and pelvis. An amphiarthrosis joint permits only slight movement. Structurally, it may be a fibrous or cartilaginous joint.eg vertebral in the spine. A diarthrosis joint is a freely movable joint. Structurally, it is always a synovial joint.eg knee and the shoulder joint
Types of synovial joints 1.Hinge joint Permits flexion and extension. Elbow joint is a notable example. 2.Saddle joint-is a synovial joint where one of the bones forming the joint is shaped like a saddle with the other bone resting on it like a rider on a horse. Concave and convex joint surfaces unite at saddle joints, e.g. thumb and carpal bones Metatarsophalangeal joint (toes) 3. Plane/gliding joint Permit gliding or sliding movements, e.g. Acromioclavicular joint (collarbone to shoulder blade),carpals of the wrist
4. Pivot joint Allows rotation; a round bony process fits into a bony ligamentous socket. Examples include the atlantoaxial joint & proximal radio-ulnar joint (top of the neck and elbow). 5. Condyloid joint Permits flexion & extension, adduction, abduction & circumduction e.g. Metacarpophalangeal joint (in the middle of your hand),wrist joint 6. Ball & Socket Permits movement in several axis; a rounded head fits into a concavity. An example is the glenohumeral joint (shoulder).
JOINT DISEASES OSTEOARTHRITIS Also called degenerative joint disease or “wear and tear” arthritis, osteoarthritis (OA) is the most common chronic condition of the joints. It occurs when the cartilage or cushion between joints breaks down leading to pain, stiffness and swelling. pain. RHEUMATOID ARTHRITIS Is an autoimmune, chronic inflammatory disorder that can affect more than just your joints. In some people, the condition also can damage a wide variety of body systems, including the skin, eyes, lungs, heart and blood vessels. The disease affects the small joints
Symptoms. joint pain in the feet, hands, and knees swollen joints fever tender joints
loss of joint function, stiff joints, fatigue, joint redness, rheumatoid nodules, joint warmth, joint deformity GOUTY ARTHRITIS Is a form of inflammatory arthritis that develops in some people who have high levels of uric acid in the blood. Gout is one of the most painful forms of arthritis. It occurs when too much uric acid builds up in the body. The buildup of uric acid can lead to: Sharp uric acid crystal deposits in joints, often in the big toe at the metatarsalphalangeal joint
SEPTIC ARTHRITIS Septic arthritis is inflammation of a joint caused by a bacterial infection. It is also known as infectious or bacterial arthritis. The condition is most commonly caused by staphylococcal or streptococcal bacteria. POST-TRAUMATIC ARTHRITIS Is caused by the wearing out of a joint that has had any kind of physical injury. The injury could be from sports, a vehicle accident, a fall, a military injury, or any other source of physical trauma. Such injuries can damage the cartilage and/or the bone, changing the mechanics of the joint and making it wear out more quickly. MIGRATORY ARTHRITIS Occurs when pain spreads from one joint to another. In this type of arthritis, the first joint may start to feel better before pain starts in a different joint. Although migratory arthritis can affect people who have other forms of arthritis, it can also result from a serious illness.