1. The Appendicular Skeleton

2. THE SKELETAL SYSTEM The Appendicular Skeleton
2 pairs of limbs and 2 girdles
Pectoral (shoulder) girdle attaches upper limbs
Pelvic (hip) girdle secures lower limbs
3-Segmented limbs
Upper = arm
Arm
Forearm
Hand
Lower = leg
Thigh
Leg
Foot

3. Pectoral Girdle (Shoulder Girdle)
Clavicle – anterior: collar bone
Sternal end attaches to the manubrium medially
Acromial end articulates with the scapula laterally
Scapula – posterior: shoulder blade

4. Scapulae: triangular, paired, but don’t connect in back (adds thoracic flexibility)

5. Scapula Glenoid cavity articulates with the humerus
Acromium articulates with clavicle
Coracoid process projects anteriorly

6. Upper extremity Arm or Brachium = upper arm Forearm or Antebrachium
Between shoulder and elbow (humerus)
Forearm or Antebrachium
Radius & ulna
Hand includes:
Wrist (carpus)
Palm (metacarpus)
Fingers (phalanges)

7. Arm Humerus is the only bone
Head of humerus fits into glenoid cavity of scapula
Distal & medially, trochlea articulates with the ulna
Distal & laterally capitulum articulates with the radius
Medial & lateral epicondyles

8. Right humerus, anterior view

9. Right humerus, posterior view

10. Forearm 2 bones: articulate with each other proximally and distally
Radius is thinner proximally, like a spool of thread, and wide distally; ulna is slightly longer and looks like a monkey wrench (supposedly!)
2 bones: articulate with each other proximally and distally
Interosseous membrane between them
Ulna
Olecranon hinges with the humerus forming elbow
Styloid process distally
Radius
Contributes to wrist joint
Styloid process anchors a ligament to wrist (thumb side)

11. Right forearm bones, anterior view

12. Right forearm bones, posterior view

13. In the anatomical position, the radius is lateral (thumb side); with pronation the palm faces posteriorly and the bones cross
Left forearm
Anatomical position
Prone: body lying face down
Suppine: body lying face up
prone
(you can remember prone if you think about how you would fall forward onto your face if you passed out)
pronation moves the forearm into the prone position and supination moves it back to the anatomical position

14. Proximal and distal joints of the forearm
proximal ulna

15. Hand Proximal is “wrist” – 8 carpal bones Palm of hand - 5 metacarpals
Fingers (or digits) consist of miniature long bones called phalanges: thumb (“pollex”) has 2; fingers have 3: proximal, middle, distal
Right hand, 2 views:

18. Pelvic Girdle (Hip Girdle)
Strongly attached to axial skeleton (sacrum)
Deep sockets
More stable than pectoral (shoulder) girdle
Less freedom of movement
Made up of the paired hip bones
“Bony pelvis” is basin-like structure: hip bones plus the axial sacrum and coccyx

19. Hip bone (os coxae): 3 separate bones in childhood which fuse
Ilium
Ischium
Pubis

20. Ilium Iliac crest Anterior superior iliac spine Greater sciatic notch
Forms part of “acetabulum”
(hip socket) which receives ball-shaped head of femur
ilium

21. Ischium Body Ramus Ischial spine Ischial tuberosity Part of socket

22. Pubis Joins medially in pubic symphysis
Forms “obturator foramen” (large hole) with ischium
Part of socket
pubis
pubis

23. Hip bones with labels

24. False (greater) and
true (lesser) pelvis
Ligaments

25. Pelvis and childbearing
Male/female differences
Large & heavy vs light & delicate
Heart shaped pelvic inlet vs oval
Narrow deep true pelvis vs wide & shallow
Narrow outlet vs wide
Less than 90 degree pubic arch vs more than 90 degree
Birth canal changes shape as baby descends: head turns ¼
Higher: pelvic inlet (brim) - side to side largest
Lower: pelvic outlet - largest in AP direction

26. Lower limb
Thigh: femur
Leg (lower leg)
Tibia
Fibula
Foot

27. Thigh Femur is largest, longest and strongest bone in the body
Head fits in socket (acetabulum) of pelvis
Neck is weakest
Greater trochanter
Distal: lateral & medial condyles and epicondyles
Patella: sesmoid bone

28. Right femur, anterior view

29. Right femur, posterior view

30. Leg Tibia: shin bone Fibula Interosseous membrane
Medial and lateral condyles
Tibial tuberosity
Distal medial malleolus (medial ankle)
Fibula
Distal lateral malleolus (lateral ankle)
Interosseous membrane

31. Right lower leg, anterior view

33. Foot Tarsus: 7 tarsal bones 5 metatarsals 14 phalanges
Talus: articulates with tibia and fibula anteriorly and calcaneus posteriorly
Calcaneus: heel bone
Smaller cuboid, navicular, and 3 cunieforms (medial, intermediate and lateral)
5 metatarsals
14 phalanges
Great toe is hallux

34. Right foot, superior (dorsal) view and inferior (plantar) view

35. Right foot, lateral and medial views

36. Arches