Understanding the Appendicular Skeleton in the Human Body

1. The skeletal system: the appendicular skeleton

2. The Pectoral Girdle(Shoulder) • 2 pectoral girdles • attach bones of upper limbs to axial skeleton • each: 1 clavicle • 1 scapula

3. Clavicle • S-shaped, (medial ½ convex anteriorly, lateral ½ concave anteriorly) slender bone • lies horizontally across anterior thorax superior to 1st rib

4. Clavicle • medial end = sternal end is rounded & articulates with the manubrium @ sternoclavicular joint

5. Clavicle • lateral end = acromial end is flat • articulates with acromion of the scapula to form acromialclavicular joint

6. Clavicle • last bone to stop growing • 1 of most frequently fx’d bones (2 curves) usually from fall on outstretched arm • or see compression fx in auto accidents from shoulder strap which can cause damage to median n. (between clavicle & 2nd rib)

7. Scapula • aka shoulder blade, angel bone • large, triangular, flat bone • in superior part of posterior thorax between levels of 2nd & 7th ribs • spine: prominent ridge that runs diagonally across posterior surface

8. lateral edge: acromion a flattened expanded process, easily felt as hi pt of shoulder (tailors use it as landmark to measure length of arm) • glenoid cavity: inferior to acromion, smooth, shallow depression that accepts head of humerus in shoulder joint

9. Scapula

10. Upper Limb • 6 parts: • Humerus • Ulna • Radius • Carpals • Metacarpals • Phalanges • Joints: • Shoulder • Elbow • Wrist • Hand

11. Humerus • longest & largest bone of upper limb • articulates proximally with scapula & distally with ulna & radius • head: rounded proximal end • articulates with glenoid cavity of scapula to form glenohumeral joint

12. Humerus

13. Humerus • distal end: • capitulum: rounded knob on lateral aspect that articulates with head of radius • trochlea: medial to capitulum, spool-shaped, articulates with ulna

14. Humerus

15. Ulna • medial aspect of forearm • longer than radius • proximal end: olecranon (prominence in elbow) • distal end: head, styloid process (posterior)

16. Radius • lateral aspect of forearm • proximal end: head of radius: articulates with capitulum • distal end: styloid process (palpable proximal to thumb)

17. Ulna & Radius • connect @ 3 places • interosseous membrane • proximal end • distal end

18. Carpals • proximal to the hand, distal to radius & ulna • 8 small bones joined by ligaments • articulations w/each other called intercarpal joints

19. Carpal Tunnel

20. Metacarpals

21. Phalanges • 14 bones of the digits (each hand) • #’d I to V beginning with thumb • thumb is the pollex has only 2 phalanges, other digits have 3 • joints between phalanges called interphalangeal joints

22. Phalanges

24. Pelvic Girdle • 2 hip bones (oscoxa) which unite anteriorly at pubic symphysisand posteriorly with the sacrum @ sacroiliac joint

25. Pelvic Girdle • Functions: • provides sturdy support for vertebral column • connects lower limb to axial skeleton

26. Newborn Pelvis • 3 bones on each side: • Ilium • superior • Pubis • anterior & inferior • Ischium • posterior & inferior

27. Ilium • largest of the 3 hip bones • distinguishing features: • Iliac Crest • along superior surface • Sacroiliac Joint (SI Joint) • between sacrum and ilium

28. Ilium

29. Ischium • ramus of ischium fuses with pubis • distinguishing features: • IschialTuberosity • what you feel when someone sits on your lap

30. Ischium

31. Pubis • Acetabulum • formed by ilium, ischium, & pubis • is the “socket” half of the hip joint • Pubic Symphysis • joint between the 2 hip bones

32. True Pelvis/ False Pelvis • Pelvic Brim: line that distinguishes between true & false palvis

33. Male Pelvis • generally male bone heavier & stronger & have larger surface marker (because larger muscles attach) • Pelvis: • deeper false pelvis, smaller, narrower • pelvic brim heart-shaped • acetabulum larger, faces posterior • obturator foramen round

34. Female Pelvis • generally bones lighter & thinner • Pelvis: • false pelvis shallow, widers • pelvic brim larger, more oval • acetabulum smaller & faces anterior • obturator foramen oval

35. Male or Female?

36. Male or Female?

37. Lower Limb • 30 bones in each: • 1 femur • 1 patella • 1 tibia • 1 fibula • 7 tarsals • 5 metatarsals • 14 phalanges

38. Femur • longest, heaviest, & strongest bone in the body • proximally articulates with the acetabulum to form hip joint • Head of the Femur: “ball” part of joint • small, central depression: fovea capitis • Greater Trochanter • prominence felt & seen @ side of hip

39. Femur

40. Femur • distally articulates with: • Patella • Tibia

41. Patella (kneecap) • small, triangular, sesamoid bone • develops in tendon of quadriceps femoris muscle • Parts: • Base: broad, superior end • Apex: pointed, inferior end

42. Patella

43. Tibia “shin bone” larger, medial, weight-bearing bone of lower leg proximally articulates with femur & fibula distally articulates with fibula & tarsals

44. Tibia • medial malleolus forms prominence that is palpable & visible on medial ankle

45. Fibula • parallel & lateral to the tibia & considerably smaller • head of fibula on proximal end • lateral malleolus at distal end

46. Tibia & Fibula

47. Tarsals • 7 bones: • 1 calcaneous: heel bone, largest of the tarsals

48. Metatarsals • 5 bones between tarsals & phalanges • #’d I to V from medial  lateral

49. Phalanges • 14 bones that make up the 5 digits • #’d I to V medial to lateral • Hallux: great or big toe has 2 large heavy phalanges

50. Arches of the Foot • 2 arches in foot: • allows the foot to support weight of body by distributing weight over the soft & hard tissues • provide leverage while walking fully developed by age 12 - 13