Bones, Part 1: the Appendicular Skeleton

PowerPoint® Lecture Slides The Appendicular Skeleton prepared by Leslie Hendon University of Alabama, Birmingham • Pectoral girdle • Attaches the upper limbs to the trunk Pelvic girdle C H A P T E R • 8 • Attaches the lower limbs to the trunk Part 1 • Upper and lower limbs differ in function Bones, • Share the same structural plan Part 1: The Appendicular Skeleton

The Pectoral Girdle The Pectoral Girdle

• Consists of the clavicle and the scapula • Provides attachment for many muscles that • Pectoral girdles do not quite encircle the move the upper limb body completely • Girdle is very light and upper limbs are • Medial end of each clavicle articulates with mobile the manubrium and first rib • Only clavicle articulates with the axial skeleton • Laterally—the ends of the clavicles join the • Socket of the shoulder joint (glenoid cavity) is scapulae shallow • Scapulae do not join each other or the axial • Good for flexibility, bad for stability skeleton

Articulated Pectoral Girdle Clavicles Sternal (medial) Clavicle end Acromio- clavicular Scapula Posterior joint

Anterior Acromial (lateral) end (b) Right clavicle, superior view

Acromial end Anterior Trapezoid line Sternal end

Posterior Tuberosity for PLAY Shoulder Conoid tubercle costoclavicular ligament (a) Articulated pectoral girdle (c) Right clavicle, inferior view Copyright © 2011 Pearson Education, Inc. Figure 8.1a Copyright © 2011 Pearson Education, Inc. Figure 8.1b, c

1 Scapulae Structures of the Scapula Acromion Suprascapular notch Superior border

• Lie on the dorsal surface of the rib cage Coracoid Superior process angle • Located between ribs 2–7 Glenoid cavity • Have three borders • Superior • Medial (vertebral)

• Lateral (axillary) Subscapular Lateral border fossa • Have three angles Medial border • Lateral, superior, and inferior

(a) Right scapula, anterior aspect Inferior angle

Structures of the Scapula Structures of the Scapula Coracoid process Supraspinous fossa Suprascapular notch Acromion Supraglenoid tubercle Superior Acromion angle Supraspinous fossa Coracoid Supraspinous process fossa Glenoid cavity Spine Glenoid Spine Infraspinous Subscapular cavity at lateral fossa fossa angle Infraglenoid Infraspinous Infraspinous fossa tubercle fossa Posterior Anterior

Subscapular fossa Medial border Lateral border

The Upper Limb Arm

• 30 bones form each upper limb • Region of the upper limb between the • Grouped into bones of the: shoulder and elbow • Arm • Humerus • Forearm • The only bone of the arm • Hand • Longest and strongest bone of the upper limb • Articulates with the scapula at the shoulder • Articulates with the radius and ulna at the elbow

2 Structures of the Humerus of the Right Arm Structures of the Humerus of the Right Arm: the elbow

Greater tubercle Head of humerus Head of humerus Greater tubercle Lesser tubercle Humerus Anatomical neck Anatomical neck Humerus Coronoid Olecranon Intertubercular Surgical neck fossa sulcus fossa

Medial Capitulum Olecranon epicondyle process Radial groove Deltoid tuberosity Deltoid tuberosity Lateral epicondyle Medial Head of Trochlea epicondyle Medial supracondylar radius ridge Coronoid Radial process of Head Lateral supracondylar Coronoid fossa ulna tuberosity Neck ridge Olecranon fossa Radial notch Radial fossa Medial epicondyle Radius Ulna Ulna Medial epicondyle Lateral epicondyle Radius Capitulum (b) Posterior view Trochlea (a) Anterior view Trochlea (c) Anterior view at the elbow region (d) Posterior view of extended elbow

Forearm Ulna and Radius

• Formed from the radius and ulna • Ulna • Proximal ends articulate with the humerus • Main bone responsible for forming the elbow joint with the humerus • Hinge joint allows forearm to bend on arm • Distal ends articulate with carpals • Distal end is separated from carpals by fibrocartilage • Radius and ulna articulate with each other at the • Plays little to no role in hand movement proximal and distal radioulnar joints • Radius • The interosseous membrane • Superior surface of the head of the radius articulates with the capitulum • Interconnects radius and ulna • Medially—the head of the radius articulates with the radial notch of the • In anatomical position; the radius is lateral and the ulna ulna is medial • Contributes heavily to the wrist joint • Distal radius articulates with carpal bones • When radius moves, the hand moves with it

Proximal Part of the Ulna Radius and Ulna Olecranon process

View Trochlear notch Olecranon Radial notch Olecranon process process of the ulna Head of radius Coronoid process Head Trochlear notch Neck Neck of radius Radial Coronoid process Radial notch tuberosity Proximal radioulnar joint

Articulation Radius for lunate Ulnar notch of the radius Articulation Ulnar notch of Radius for scaphoid the radius Head of ulna Head of ulna Styloid Styloid process Styloid process Distal radioulnar joint process of radius Styloid process of ulna of ulna (a) Anterior view (b) Posterior view Styloid process of radius View Head of Styloid ulna process (d) Distal ends of the radius and ulna at the wrist Copyright © 2011 Pearson Education, Inc. Figure 8.4a, b Copyright © 2011 Pearson Education, Inc. Figure 8.4c, d

3 Proximal Ends of the Radius and Ulna at the Hand elbow • Includes the following bones Humerus Humerus Coronoid Olecranon fossa fossa • Carpus—wrist

Medial Capitulum Olecranon epicondyle • Metacarpals—palm process Lateral epicondyle • Phalanges—fingers Medial Head of Trochlea epicondyle radius Coronoid Radial process of Head ulna tuberosity Neck Radial notch Radius Ulna Ulna Radius

Carpus Bones of the Hand • Forms the true wrist—the proximal region of the hand Phalanges • Gliding movements occur between carpals Distal Middle • Composed of eight marble-sized bones Proximal • Carpal bones • Are arranged in two irregular rows • Proximal row from lateral to medial Metacarpals Head • Scaphoid, lunate, triquetral, and pisiform Sesamoid Shaft bones Base Carpals 4 5 3 2 • Distal row from lateral to medial Hamate 1 Carpals 2 3 4 1 5 Carpals Capitate Trapezium Hamate • Trapezium, trapezoid, capitate, and hamate Pisiform Trapezoid Capitate Triquetrum Scaphoid Triquetrum • A mnemonic to help remember carpals: Lunate Lunate • Sally left the party to take Carmen home Ulna Radius Ulna (a) Anterior view of right hand (b) Posterior view of right hand

• Metacarpus • Five metacarpals radiate distally from the wrist • Metacarpals form the palm • Numbered 1–5, beginning with the pollex (thumb) • Articulate proximally with the distal row of carpals • Articulate distally with the proximal phalanges

• Phalanges • Numbered 1–5, beginning with the pollex (thumb) • Except for the thumb, each finger has three phalanges • Proximal, middle, and distal

4 Pelvic Girdle

• Attaches lower limbs to the spine • Supports visceral organs • Attaches to the axial skeleton by strong ligaments • Acetabulum is a deep cup that holds the head of the femur • Lower limbs have less freedom of movement • Are more stable than the arm • Consists of paired hip bones (coxal bones) • Hip bones unite anteriorly with each other • Articulates posteriorly with the sacrum

Bones of the Pelvic Girdle The Pelvic Girdle

Base of sacrum Iliac crest • Consists of three separate bones in childhood Sacroiliac joint • Ilium, ischium, and pubis Iliac fossa Anterior superior • Bones fuse, retain separate names to regions of the iliac spine coxal bones llium Sacral promontory Coxal • Acetabulum Anterior bone Sacrum (os coxae inferior iliac • A deep hemispherical socket on lateral pelvic surface spine or hip bone) Pubis Coccyx Pelvic brim Acetabulum Pubic tubercle

Ischium Pubic crest Pubic (a) Pelvic girdle Pubic arch symphysis

PLAY Pelvis

Ischium Ilium • Forms posteroinferior region of the coxal bone • Anteriorly—joins the pubis • Large, flaring bone • Ischial tuberosities • Forms the superior region of the coxal bone • Are the strongest part of the hip bone • Site of attachment for many muscles Pubis • Articulation with the sacrum forms sacroiliac joint • Forms the anterior region of the coxal bone • Lies horizontally in anatomical position • Pubic symphysis • The two pubic bones are joined by fibrocartilage at the midline • Pubic arch—inferior to the pubic symphysis • Angle helps distinguish male from female pelves

5 Lateral and Medial Views of the Hip Bone True and False Pelves

Tubercle of the iliac crest Ilium Ilium • Bony pelvis is divided into two regions Ala Anterior gluteal line Iliac fossa Iliac crest Iliac crest Posterior • False (greater) pelvis—bounded by alae of gluteal line Anterior Anterior Posterior the iliac bones superior superior superior Posterior iliac spine iliac spine iliac spine superior Inferior gluteal line iIiac spine Posterior • True (lesser) pelvis—inferior to pelvic brim Posterior inferior Anterior inferior Anterior inferior inferior iliac spine iliac spine iliac spine Body of iliac spine Arcuate the ilium Greater sciatic Acetabulum Auricular line notch surface • Forms a bowl containing the pelvic organs Ischial body Superior ramus of pubis Ischial spine Ischial spine Pubic tubercle Obturator Lesser sciatic Pubic body notch foramen

Ischium Pubis Articular surface of Ischium Ischial pubis (at pubic Ilium symphysis) Ischial ramus tuberosity Inferior ramus Ischium Ischial ramus of pubis Inferior ramus (c) Medial view, right hip bone Pubis (b) Lateral view, right hip bone of pubis

True and False Pelves Pelvic Structures and Childbearing Plane through midpelvis

Anterior • Major differences between male and female abdominal wall pelves False • Female pelvis is adapted for childbearing pelvis • Pelvis is lighter, wider, and shallower than Pelvic brim, defining in the male pelvic inlet True pelvis • Provides more room in the true pelvis Symphyseal surface Coccyx

Female and Male Pelves Female and Male Pelves

6 The Lower Limb Thigh

• Carries the entire weight of the erect body • The region of the lower limb between the hip • Bones of lower limb are thicker and stronger and the knee than those of upper limb • Femur—the single bone of the thigh • Divided into three segments • Longest and strongest bone of the body • Thigh, leg, and foot • Ball-shaped head articulates with the acetabulum

Structures of the Femur Patella Neck Fovea Greater capitis trochanter Head Inter- Lesser trochanter trochanteric • Triangular sesamoid bone Intertrochanteric crest line • Imbedded in the tendon that secures the Gluteal tuberosity quadriceps muscles

Linea aspera • Protects the knee anteriorly • Improves leverage of the thigh muscles

Medial and Lateral across the knee lateral supra- condyle condylar lines Lateral Intercondylar fossa epicondyle Medial condyle Lateral Adductor tubercle epicondyle Medial Patellar epicondyle surface (b) Femur (thigh bone) Anterior view Posterior view Copyright © 2011 Pearson Education, Inc. Figure 8.10b Copyright © 2011 Pearson Education, Inc.

Leg Structures of the Tibia and Fibula • Refers to the region of the lower limb between the knee and the ankle • Composed of the tibia and fibula • Tibia—more massive medial bone of the leg • Receives weight of the body from the femur • Fibula—stick-like lateral bone of the leg • Interosseous membrane • Connects the tibia and fibula • Tibia articulates with femur at superior end • Forms the knee joint • Tibia articulates with talus at the inferior end • Forms the ankle joint • Fibula does not contribute to the knee joint • Stabilizes the ankle joint

7 Structures of the Tibia and Fibula The Foot • Foot is composed of Lateral Lateral condyle • Tarsus, metatarsus, and the phalanges condyle Fibula Tibial articulates • Important functions tuberosity here • Supports body weight • Acts as a lever to propel body forward when walking Line for • Segmentation makes foot pliable and adapted to soleus muscle uneven ground (c) Anterior view, proximal tibia (d) Posterior view, proximal tibia

Fracture sites

Tarsus Phalanges of the Toes • Makes up the posterior half of the foot • Contains seven bones called tarsals • 14 phalanges of the toes • Body weight is primarily borne by the talus and calcaneus • Trochlea of the talus • Smaller and less nimble than those of the fingers • Site of articulation with the tibia • Structure and arrangement are similar to phalanges of • Other tarsals are: fingers • Cuboid and navicular • Except for the great toe, each toe has three • Medial, intermediate, and lateral cuneiforms phalanges • Proximal, middle, and distal Metatarsus • Consists of five small long bones called metatarsals • Numbered 1–5 beginning with the hallux (great toe) • First metatarsal supports body weight

Bones of the Foot Bones of the Foot

Sustentaculum Facet for Talus Phalanges tali (talar shelf) medial Distal malleolus Middle Navicular Proximal Intermediate cuneiform 1 2 3 First metatarsal 4 Metatarsals Medial 5 cuneiform

Intermediate Lateral cuneiform cuneiform Navicular Cuboid Medial Calcaneus Tarsals Talus cuneiform Calcaneal Trochlea (b) Medial view of talus tuberosity Calcaneus

8 Bones of the Foot Arches of the Foot Facet for Navicular Intermediate cuneiform lateral malleolus Lateral cuneiform • Foot has three important arches • Medial and lateral longitudinal arch Talus • Transverse arch

Calcaneus Cuboid Fifth metatarsal (c) Lateral view

PLAY Bones of the Foot

Arches of the Foot Arches of the Foot

Medial longitudinal arch Transverse arch Lateral longitudinal arch

Lower Limb and Pelvis Disorders of the Appendicular Skeleton

• Bone fractures • Hip dysplasia • Head of the femur slips out of acetabulum • Clubfoot • Soles of the feet turn medially

9 The Appendicular Skeleton Throughout Life Changes in Body Proportions

• Growth of the appendicular skeleton • Increases height • Changes body proportions • Upper/lower body ratio changes with age • At birth, head and trunk are 1.5 times as long as lower limbs • Lower limbs grow faster than the trunk • Upper/lower body ratio of 1 to 1 by age 10

The Appendicular Skeleton Throughout Life

• Few changes occur in adult skeleton until middle age, when • Skeleton loses mass • Osteoporosis and limb fractures become more common