The Skeletal System:

1. The Skeletal System: The Appendicular Skeleton

2. I. Introduction A. The appendicular skeleton includes the bones of the upper and lower extremities and the shoulder and hip girdles.

3. I. Introduction B. The appendicular skeleton functions primarily to facilitate movement.

4. II. Pectoral (Shoulder) Girdle • The pectoral girdle attaches the bones of the upper limbs to the axial skeleton.

5. II. Pectoral (Shoulder) Girdle 1. The clavicle or collar bone lies horizontally in the superior and anterior part of the thorax and articulates with the sternum and the scapula.

7. II. Pectoral Girdle Continue The clavicle, one of the most frequently broken bones in the body

8. II. Pectoral Girdle Continue 2. The scapula or shoulder blade articulates with the clavicle and the humerus.

10. II. Pectoral Girdle Continue The scapulae is held in place posteriorly only by complex shoulder and back musculature.

11. III. Upper Limb • Each upper limb consists of 30 bones including the humerus, ulna, radius, carpals, metacarpals, and phalanges.

13. III. Upper Limb 1. The humerus is the longest and largest bone of the upper limb.

14. III. Upper Limb It articulates proximally with the scapula at the glenohumeral joint, and distally at the elbow with both the radius and ulna.

15. III. Upper Limb Continue 2. The ulna is located on the medial aspect of the foramen.

16. III. Upper Limb Continue 3. The radius is located on the lateral aspect (thumb side) of the foramen.

17. III. Upper Limb Continue • Falling on an outstretched arm may create a Colle’s fracture, a fracture near the distal end.

18. Upper Limb Continue The radius and ulna articulate with the humerus at the elbow joint, with each other, and with three carpal bones.

19. Upper Limb Continue 4. Carpals, Metacarpal, Phalanges

21. Upper Limb Continue The eight carpal bones, bound together by ligaments, comprise the wrist.

22. Upper Limb Continue • Because of the scant blood supply to the scaphoid, scaphoid fractures may be very slow to heal.

23. III. Upper Limb Continue Five metacarpal bones are contained in the palm of each hand.

25. III. Upper Limb Continue Each hand contains 14 phalnges, three in each finger and two in in each thumb.

27. IV. Pelvic Girdle • The pelvic (hip) girdle consists of two hipbones (coxal bones) on which the weight of the body is carried.

28. IV. Pelvic Girdle • Each hipbone is composed of three separate bones at birth: • Ilium • pubis • ischium.

29. IV. Pelvic Girdle • These bones eventually fuse at a depression called the acetabulum, which forms the socket for the hip joint.

31. IV. Pelvic Girdle • The ilium is the largest and articulates (fuses) with the ischium and pubis.

33. IV. Pelvic Girdle • The ischium is the inferior, posterior portion of the hip bone.

35. IV. Pelvic Girdle • The pubis is the anterior and inferior part of the hip bone.

37. IV. Pelvic Girdle Continue B. True or False Pelves 1. Together with the sacrum and coccyx, the two hipbones form the pelvis.

38. IV. Pelvic Girdle Continue 2. The greater (false) and lesser (true) pelvis are anatomicaly separated by a plane at the pelvic brim.

40. V. Comparison of Male and Female • Female and male pelvic girdles differences are primarily related to the need for a larger outlet in females to facilitate childbirth.

41. V. Comparison of Female and Male Pelves • Male bones are larger and heavier than those of the female

42. V. Comparison of Female and Male Pelves • Male’s joint surfaces also tend to be larger.

43. V. Comparison of Female and Male Pelves • Muscle attachment points are more well-defined in the bones of a male than of a female due to the larger size of the muscles in males.

44. V. Comparison of Female and Male Pelves • Iliac bones of male more vertical

45. V. Comparison of Female and Male Pelves • Pelvic brim in male is heart shaped due to prominence of the sacral promontary

47. V. Comparison of Female and Male Pelves • Pelvic brim more oval in female

49. V. Comparison of Female and Male Pelves • Pubic arch in male is under 90 degrees