The appendicular skeleton

1. The appendicular skeleton Appendicular skelton + skeletal muscles= movement

2. Bones of the appendicular skeleton • 2 pectoral girdles • Clavicles, scapulae • 2 upper extremities • Pelvic girdle • Coxae (hip bones) • 2 lower extremities

3. Some important external features of bones • Processes where tendons and ligaments attach • Trochanter, tuberosity- large and small • Tubercle- rounded • Crest- ridge • Spine- pointed • Processes formed at articulations • Head, condyle, facet • Depressions and openings • Fossa, sulcus, foramen, sinus

4. Pectoral girdle

5. The clavicle • Joint between clavicle and sternum is only direct connection between axial skeleton, shoulder girdle • Easily fractured

6. Scapula (shoulder blade) • Glenoid cavity articulates with head of humerus to form shoulder joint • Acromion forms tip of shoulder; articulates with clavice • Coracoid process is an attachment site

7. Upper limb • Arm (humerus) • Glenohumeral joint • Distal end articulates with radius and ulna • Forearm • Radius (lateral), ulna (medial) • Fibrous membrane connects the two

8. Wrist and hand • 8 carpals, 5 metacarpals, 14 phalanges • Carpal tunnel formed by space between hamate and pisiform; scaphoid and trapezium • Median nerve and flexor tendons pass through it

9. Pelvic girdle is much more massive than pectoral girdle • Pelvis: two coxae, sacrum, coccyx • Coxa formed by ileum, ischium and pubis • Obturator foramen is largest in skeleton

10. Male and female pelves wider Female pelvis is lighter and shallower Wider outlet

11. Pectoral vs pelvic girdle • Pectoral does not articulate directly with vertebrae • Pectoral girdle provides more mobility than strength • Pelvic girdle provides more strength than mobility

12. Lower limb • Femur is longest, strongest, heaviest bone • Articulates with pelvis at acetabulum • Articulates with tibia and fibula at distal end • Tibia and fibula form lower leg • Fibula is attachment site; does not bear weight or help form knee joint • Fibrous membrane between the two

13. Bones of ankle and foot • Seven tarsals; talus articulates with tibia and fibula • Standing, most weight is supported by calcaneus • Muscles attached to calcaneus by Achilles tendon • Metatarsal bones carry the rest

14. Arches of the foot • Longitudinal arch • Begins at calcaneus, extends to heads of metatarsals • Transverse arch • Formed by tarsals and bases of metatarsals • Normally ball of foot carries 40% of weight and heel 60%

15. Bone and joint disorders • Bone structure and remodeling is affected by: • Age (osteopoenia) • Physical stress • Hormone levels • Rates of calcium and phosphate absorption and excretion • Genetic and environmental factors

16. Diagnosing skeletal disorders • Limitation of movement • Joint involvement (mono-or polyarthritic?) • Inflammation • Sounds (bony crepitus)- grating sounds • Abnormal bone deposits around fractures or joints • Abnormal posture

17. Congenital disorders • Osteogenesis imperfecta- lack of bone collagen fibers • Marfan’s syndrome- connective tissue disorder affects heart as well • Achondroplasia-epiphyseal plates are replaced by bone • Clubfoot(congenital talipes equinovarus) abnormal muscle development • Cleft palate • Spina bifida

19. infections • Osteomyelitis usually caused by S. aureus • Paget’s disease apparently caused by virus

20. Malnutrition and bone disorders scurvy rickets

21. Secondary disorders can also affect skeleton • Endocrine (giantism) • Autoimmune (rheumatoid arthitis) • Gout (digestive) • How do joints faciliate bone movement?