Chapter 8: The Appendicular Skeleton

1. Chapter 8:The Appendicular Skeleton

2. Appendicular Skeleton • 126 bones • Consists of limbs and limb girdles to provide movement • Pectoral girdle: 4 bones • Upper limbs: 60 bones • Pelvic girdle: 2 bones • Lower limbs: 60 bones

4. Upper limbs • Carpal tunnel syndrome • Carpals arranged in two rows of four bones • Creates a U shape enclosed by the flexor retinaculum (ligament) • All tendons, vessels, and nerves of the hand must pass through channels between bones and ligaments (no extra space) • Any inflammation = pressure on nerves leading to pain

5. The Appendicular Skeleton • Allows us to move and manipulate objects • Includes all bones besides axial skeleton: • the limbs • the supportive girdles

6. The bones of the pectoral girdle, their functions, and features.

7. The Pectoral Girdle Figure 8–2a

8. The Pectoral Girdle • Also called the shoulder girdle • Connects the arms to the body • Positions the shoulders • Provides a base for arm movement

9. The Pectoral Girdle • Consists of: • 2 clavicles • 2 scapulae • Connects with the axial skeleton only at the manubrium

10. The Clavicles Figure 8–2b, c

11. The Clavicles • Also called collarbones • Long, S-shaped bones • Originate at the manubrium (sternal end) • Articulate with the scapulae (acromial end) • Costal Tuberosity: • Attachment for the costoclavicular ligament which articulates with the cartilage of the ribs • Conoid Tubercle: • Attachment for the conoid ligament which articulates with the coracoid process of the scapula

12. The Scapulae • Also called shoulder blades • Broad, flat triangles • Articulate with arm and collarbone

13. The Scapula • Anterior surface: the subscapular fossa • attachment for the subscapularis muscle • Function to rotate the head of the humerus medially (internal rotation) • Function to draw the humerus forward and downward when the arm is raised Figure 8–3a

14. Structures of the Scapula • Posterior surface • Supraspinous fossa • Origin for the supraspinatus muscle, which abducts (toward midline) the arm at the shoulder • Origin for the infraspinatus muscle, which adducts that arm Figure 8–3c

15. Why would a broken clavicle affect the mobility of the scapula? Muscles attach the clavicle to the scapula. Clavicle is attached to the sternum which is attached to the scapula. Clavicle attaches the scapula to the humerus. Clavicle attaches the scapula to the sternum.

16. The bones of the upper limbs, their functions, and features.

17. The Upper Limbs • Arms, forearms, wrists, and hands Note: arm (brachium) = 1 bone, the humerus

18. The Humerus • Also called the arm • The long, upper armbone • Greater tuberosity • Attachment for suprasinatus and infrapinatus • Lesser tuberosity • Attachment for tendon of subscapularus Figure 8–4

19. The Humerus • Epicondyle • Attachment for ligaments of the elbow-joint • Lateral: tendon of supinator muscle • Medial: tendon of flexor muscles of the forearm • Olecranon fossa • Receives process for the extension of the forearm • Coronoid fossa • Receives the coronoid process of the ulna during flexion (joint angle decreases) of the forearm Figure 8–4

20. The Forearm • Also called the antebrachium • Consists of 2 long bones: • ulna (medial) • radius (lateral) • Radial Tuberosity • Insertion of bicep brachii • Ulnar Tuberosity • Insertion of brachialis • Styloid Process • Muscle attachment for ulna or radius Figure 8–5

21. The rounded projections on either side of the elbow are parts of which bone? humerus ulna radius both A and B

22. Which bone of the forearm is lateral in the anatomical position? ulna radius scaphoid depends on hand position

23. The Wrist Figure 8–6

24. Bill accidentally fractures his first distal phalanx with a hammer. Which finger is broken? thumb small finger ring finger index finger

25. The bones of the pelvic girdle, their functions, and features.

26. The Pelvic Girdle • Made up of 2 hipbones (ossa coxae) • Strong to bear body weight, stress of movement • Part of the pelvis

27. Pelvic Girdle • 2 os coxae • Note: • “pelvis” (no anatomical) = pelvic girdle (2 os coxae) + sacrum + coccyx

28. The Pelvic Girdle Figure 8–7

29. The Pelvis Figure 8–8

30. The Pelvis • Consists of 2 ossa coxae, the sacrum, and the coccyx • Stabilized by ligaments of pelvic girdle, sacrum, and lumbar vertebrae • Obturator Foramen • Opening for nerves and muscles to pass through • Acetabulum • Head of the femur meets with the pelvis; hip-joint • Ischial Tuberosity • Point of insertion for the semimembranosus, head of biceps femoris, and semitendinosus

31. Which three bones make up the os coxae? ilium, ischium, and femur ilium, ischium, and pubis ilium, acetabulum, and pubis ilium, femur, and pubis

32. When you are seated, which part of the pelvis bears your body’s weight? obturator foramen posteriorinferior iliac spines ischial tuberosities pubic tubercle

33. Divisions of the Pelvis Figure 8–9

34. Divisions of the Pelvis • True pelvis: • encloses pelvic cavity • 2 regions: • Pelvic brim: encloses pelvic inlet • Perineum region: perineal muscles support organs of pelvic cavity • False pelvis: • blades of ilium above arcuate line

35. The structural and functional differences between the male and female pelvis.

36. Comparing the Male and Female Pelvis • Female pelvis: • Smoother and lighter • less prominent muscle and ligament attachments

37. Pelvis Modifications for Childbearing • Enlarged pelvic outlet • Broad pubic angle (> 100°) • Less curvature of sacrum and coccyx • Wide, circular pelvic inlet • Broad, low pelvis

38. How is the pelvis of females adapted for childbearing? narrow pubic angle greater curvature on sacrum broad, low pelvis oval pelvic inlet

39. The bones of the lower limbs, their functions, and features.

40. The Lower Limbs • Functions: • weight bearing • motion Note: leg = lower leg; thigh = upper leg

41. Bones of the Lower Limbs • Femur (thigh) • Patella (kneecap) • Tibia and fibula (leg) • Tarsals (ankle) • Metatarsals (foot) • Phalanges (toes)

42. The Femur • The longest, heaviest bone Figure 8–11

43. Femur • Trochanters • Greater and lesser trochanters • tendon attachments • Shaft: • attaches hip muscles • Epicondyle: • Lateral and Medial epicondyle • Attachments for ligaments of the knee joint

44. The Patella Figure 8–12

45. The Patella • Also called the kneecap • A sesamoid bone • Formed within tendon of quadriceps femoris • Base attaches quadriceps femoris • Apex attaches patellar ligament

46. The Tibia Figure 8–13

47. The Tibia • Also called the shinbone • Supports body weight • Larger than fibula • Medial to fibula • Tibial Tuberosity • Attachment for the ligamentum patellae

48. The Fibula • Attaches muscles of • feet and toes • Smaller than tibia • Lateral to tibia

49. The fibula neither participates in the knee join nor bears weight. When it is fractured, however, walking becomes difficult. Why? Fibula helps stabilize the ankle joint. Fibula attaches many leg muscles. Both A and B. None of the above.

50. The Ankle • Also called the tarsus: • consists of 7 tarsal bones • Talus: • carries weight from tibia across trochlea • Calcaneus (heel bone): • transfers weight from talus to ground • attaches Achilles tendon Figure 8–14a