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 Humerus Radius & Ulna Hand – Lower = leg Femur Tibia & Fibula Foot

3. Pectoral Girdle (Shoulder Girdle) Clavicle – anterior: collar bone Scapula – posterior: shoulder blade

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

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

6. Arm – Humerus is the only bone – Head of humerus fits into scapula – Distal & medially, articulates with the ulna – Distal & laterally articulates with the radius Arm

7. Right humerus, anterior view

8. Right humerus, posterior view

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

10. Right forearm bones, anterior view

11. Right forearm bones, posterior view

12. In the anatomical position, the radius is lateral (thumb side); with pronation the palm faces posteriorly and the bones cross Left forearm Prone: Turning the hand so that the palm is down Suppine: Turning the hand so that the palm is up Anatomical position prone pronation moves the forearm into the prone position and supination moves it back to the anatomical position

13. proximal ulna Proximal and distal joints of the forearm

14. 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:

17. 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

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

19. Ilium Forms part of hip socket which receives ball- shaped head of femur ilium

20. Hip bones with labels

21. 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

22. Male vs. Female Pelvis

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

24. Thigh Femur is largest, longest and strongest bone in the body Head fits in socket of pelvis Neck is weakest

25. Right femur, anterior view

26. Right femur, posterior view

27. Leg Tibia: shin bone Fibula – Interosseous membrane

28. Right lower leg, anterior view

30. Foot Tarsus: 7 tarsal bones – 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

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

32. Right foot, lateral and medial views

33. Arches