Sacral promontory Ala Body of first sacral vertebra
Sacral promontory Ala Body of first sacral vertebra Transverse ridges (sites of vertebral fusion) Apex Anterior sacral foramina Coccyx (a) Anterior view Figure 7. 21 a
Ala Sacral canal Body Facet of superior articular process Auricular surface Median sacral crest Posterior sacral foramina Coccyx Lateral sacral crest Sacral hiatus (b) Posterior view Figure 7. 21 b
Thoracic Cage • Composed of • Thoracic vertebrae • Sternum • Ribs and their costal cartilages • Functions • Protects vital organs of thoracic cavity • Supports shoulder girdle and upper limbs • Provides attachment sites for many muscles, including intercostal muscles used during breathing
Sternum (Breastbone) • Three fused bones • Manubrium • Articulates with clavicles and ribs 1 and 2 • Body • Articulates with costal cartilages of ribs 2 through 7 • Xiphoid process • Site of muscle attachment • Not ossified until ~ age 40
Ribs and Their Attachments • 12 pairs • All attach posteriorly to thoracic vertebrae • Pairs 1 through 7 • True (vertebrosternal) ribs • Attach directly to the sternum by individual costal cartilages
Ribs and Their Attachments • Pairs 8 through 12 • False ribs • Pairs 8– 10 also called vertebrochondral ribs • Attach indirectly to sternum by joining costal cartilage of rib above • Pairs 11– 12 also called vertebral (floating) ribs • No attachment to sternum
Jugular notch Clavicular notch Manubrium Sternal angle Body Xiphisternal joint Xiphoid process True ribs (1– 7) False ribs (8– 12) Sternum Intercostal spaces Costal cartilage Costal margin L 1 Vertebra Floating ribs (11, 12) (a) Skeleton of the thoracic cage, anterior view Figure 7. 22 a
Structure of a Typical Rib • Main parts: • Head • Articulates posteriorly with facets (demifacets) on bodies of two adjacent vertebrae • Neck • Tubercle • Articulates posteriorly with transverse costal facet of same-numbered thoracic vertebra • Shaft
Transverse costal facet (for tubercle of rib) Angle of rib Superior costal facet (for head of rib) Body of vertebra Head of rib Intervertebral disc Neck of rib Tubercle of rib Shaft Sternum Crosssection of rib Costal groove Costal cartilage (a) Vertebral and sternal articulations of a typical true rib Figure 7. 23 a
Articular facet on tubercle of rib Spinous process Shaft Ligaments Neck of rib Head of rib Transverse costal facet (for tubercle of rib) Body of thoracic vertebra Superior costal facet (for head of rib) (b) Superior view of the articulation between a rib and a thoracic vertebra Figure 7. 23 b
Appendicular Skeleton • Bones of the limbs and their girdles • Pectoral girdle attaches the upper limbs to the body trunk • Pelvic girdle secures the lower limbs
Pectoral Girdle (Shoulder Girdle) • Clavicles and the scapulae • Attach the upper limbs to the axial skeleton • Provide attachment sites for muscles that move the upper limbs
Acromioclavicular joint Clavicle Scapula (a) Articulated pectoral girdle Figure 7. 24 a
Clavicles (Collarbones) • Flattened acromial (lateral) end articulates with the scapula • Cone-shaped sternal (medial) end articulates with the sternum • Act as braces to hold the scapulae and arms out laterally
Sternal (medial) end Posterior Anterior Acromial (lateral) end (b) Right clavicle, superior view Figure 7. 24 b
Scapulae (Shoulder Blades) • Situated on the dorsal surface of rib cage, between ribs 2 and 7 • Flat and triangular, with three borders and three angles • Seven large fossae, named according to location
Acromion Suprascapular notch Superior border Coracoid process Glenoid cavity Lateral border Superior angle Subscapular fossa Medial border (a) Right scapula, anterior aspect Inferior angle Figure 7. 25 a
Suprascapular notch Coracoid process Superior angle Supraspinous fossa Spine Infraspinous fossa Acromion Glenoid cavity at lateral angle Medial border Lateral border (b) Right scapula, posterior aspect Figure 7. 25 b
Acromion Supraspinous fossa Supraglenoid tubercle Coracoid process Supraspinous fossa Infraspinous fossa Posterior Spine Glenoid cavity Infraspinous fossa Infraglenoid tubercle Subscapular fossa Anterior (c) Right scapula, lateral aspect Inferior angle Figure 7. 25 c
The Upper Limb • 30 bones form the skeletal framework of each upper limb • Arm • Humerus • Forearm • Radius and ulna • Hand • 8 carpal bones in the wrist • 5 metacarpal bones in the palm • 14 phalanges in the fingers
Humerus • Largest, longest bone of upper limb • Articulates superiorly with glenoid cavity of scapula • Articulates inferiorly with radius and ulna
Greater tubercle Lesser tubercle Intertubercular sulcus Head of humerus Anatomical neck Deltoid tuberosity Lateral supracondylar ridge Radial fossa Capitulum (a) Anterior view Coronoid fossa Medial epicondyle Trochlea Figure 7. 26 a
Bones of the Forearm • Ulna • Medial bone in forearm • Forms the major portion of the elbow joint with the humerus • Radius • Lateral bone in forearm • Head articulates with capitulum of humerus and with radial notch of ulna • Interosseous membrane connects the radius and ulna along their entire length
Radial notch of the ulna Head Neck Radial tuberosity Olecranon process Trochlear notch Coronoid process Proximal radioulnar joint Interosseous membrane Ulna Head of radius Neck of radius Radius Ulnar notch Radius of the radius Head of ulna Styloid process of ulna process Distal radioulnar Styloid process of radius joint of radius (a) Anterior view (b) Posterior view Figure 7. 27 a-b
Olecranon process Trochlear notch View Coronoid process Radial notch (c) Proximal portion of ulna, lateral view Ulnar notch of radius Articulation for lunate Articulation for scaphoid Styloid process View Styloid Head of ulna process (d) Distal ends of the radius and ulna at the wrist Figure 7. 27 c-d
Humerus Capitulum Coronoid fossa Medial epicondyle Trochlea Coronoid process of ulna Radial notch Ulna (c) Anterior view at the elbow region Head of radius Radial tuberosity Radius Humerus Olecranon process Olecranon fossa Lateral epicondyle Medial epicondyle Head Ulna Neck Radius (d) Posterior view of extended elbow Figure 7. 26 c-d
Hand: Carpus • Eight bones in two rows • Proximal row • Scaphoid, lunate, triquetrum, and pisiform proximally • Distal row • Trapezium, trapezoid, capitate, and hamate distally • Only scaphoid and lunate articulate with radius to form wrist joint
Hand: Metacarpus and Phalanges • Metacarpus • Five metacarpal bones (#1 to #5) form the palm • Phalanges • Each finger (digit), except the thumb, has three phalanges—distal, middle, and proximal • Fingers are numbered 1– 5, beginning with the thumb (pollex) • Thumb has no middle phalanx
Phalanges • Distal • Middle • Proximal Sesamoid bones Carpals • Trapezium • Trapezoid • Scaphoid Radius (a) Anterior view of left hand Metacarpals • Head • Shaft • Base Carpals • Hamate • Capitate • Pisiform • Triquetrum • Lunate Ulna Carpals • Trapezium • Trapezoid • Scaphoid Radius (b) Posterior view of left hand Figure 7. 28 a-b
Pelvic (Hip) Girdle • Two hip bones (each also called coxal bone or os coxae) • Attach the lower limbs to the axial skeleton with strong ligaments • Transmit weight of upper body to lower limbs • Support pelvic organs • Each hip bone consists of three fused bones: ilium, ischium, and pubis • Together with the sacrum and the coccyx, these bones form the bony pelvis
Base of sacrum Iliac fossa Coxal bone llium (os coxae or hip Pubic bone) bone Iliac crest Sacroiliac joint Anterior superior iliac spine Sacral promontory Sacrum Coccyx Anterior inferior iliac spine Pelvic brim Acetabulum Pubic tubercle Pubic crest Pubic symphysis Ischium Pubic arch PLAY Animation: Rotatable pelvis Figure 7. 29
Hip Bone • Three regions 1. Ilium • Superior region of the coxal bone • Auricular surface articulates with the sacrum (sacroiliac joint) 2. Ischium • Posteroinferior part of hip bone 3. Pubis • Anterior portion of hip bone • Midline pubic symphysis joint
Anterior gluteal Ilium line Ala Posterior Iliac crest gluteal line Posterior Anterior superior i. Iiac spine iliac spine Posterior inferior Inferior iliac spine gluteal line Greater sciatic Anterior inferior notch iliac spine Ischial body Acetabulum Ischial spine Pubic body Lesser sciatic notch Pubis Ischium Inferior ramus Ischial of pubis tuberosity Obturator foramen Ischial ramus (a) Lateral view, right hip bone Figure 7. 30 a
Ilium Iliac crest Iliac fossa Posterior superior iliac spine Posterior inferior iliac spine Auricular surface Greater sciatic notch Ischial spine Lesser sciatic notch Obturator foramen Ischium Anterior superior iliac spine Anterior inferior Body of iliac spine the ilium Arcuate line Superior ramus of pubis Pubic tubercle Articular surface of pubis (at pubic symphysis) Ischial ramus Inferior ramus of pubis (b) Medial view, right hip bone Figure 7. 30 b
Comparison of Male and Female Pelves • Female pelvis • Adapted for childbearing • True pelvis (inferior to pelvic brim) defines birth canal • Cavity of the true pelvis is broad, shallow, and has greater capacity
Comparison of Male and Female Pelves • Male pelvis • Tilted less forward • Adapted for support of male’s heavier build and stronger muscles • Cavity of true pelvis is narrow and deep
Comparison of Male and Female Pelves Characteristic Female Male Bone thickness Lighter, thinner, and smoother Heavier, thicker, and more prominent markings Pubic arch/angle 80˚– 90˚ 50˚– 60˚ Acetabula Small; farther apart Large; closer together Sacrum Wider, shorter; sacral curvature is accentuated Narrow, longer; sacral promontory more ventral Coccyx More movable; straighter Less movable; curves ventrally
Table 7. 4
Table 7. 4
Table 7. 4
The Lower Limb • Carries the weight of the body • Subjected to exceptional forces • Three segments of the lower limb • Thigh: femur • Leg: tibia and fibula • Foot: 7 tarsal bones in the ankle, 5 metatarsal bones in the metatarsus, and 14 phalanges in the toes
Femur • Largest and strongest bone in the body • Articulates proximally with the acetabulum of the hip and distally with the tibia and patella
Neck Fovea capitis Greater trochanter Head Intertrochanteric crest Lesser trochanter Intertrochanteric line Gluteal tuberosity Linea aspera Apex Anterior Facet for medial condyle of femur Facet for lateral condyle of femur Lateral condyle Medial and lateral supracondylar lines Surface for patellar Posterior ligament (a) Patella (kneecap) Intercondylar fossa Lateral epicondyle Medial condyle Adductor tubercle Medial epicondyle Lateral epicondyle Patellar surface Anterior view Posterior view (b) Femur (thigh bone) Figure 7. 31
Bones of the Leg • Tibia • Medial leg bone • Receives the weight of the body from the femur and transmits it to the foot • Fibula • Not weight bearing; no articulation with femur • Site of muscle attachment • Connected to tibia by interosseous membrane • Articulates with tibia via proximal and distal tibiofibular joints
Lateral condyle Head Proximal tibiofibular joint Intercondylar eminence Medial condyle Tibial tuberosity Interosseous membrane Anterior border Fibula Tibia Distal tibiofibular joint Lateral malleolus Articular surface Medial malleolus (a) Anterior view Figure 7. 32 a
Articular surface of medial condyle Medial condyle Articular surface of lateral condyle Head of fibula Interosseous membrane Tibia Fibula Articular surface Medial malleolus Lateral malleolus (b) Posterior view Figure 7. 32 b
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