Lecture 8 appendicular skeleton


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Lecture 8 appendicular skeleton

  1. 1. The Appendicular Skeleton
  2. 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. 3. PectoralGirdle(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. 4. Scapulae: triangular, paired, but don’tconnect in back (adds thoracic flexibility)
  5. 5. Scapula Glenoid cavity articulates with the humerus Acromium articulates with clavicle Coracoid process projects anteriorly
  6. 6. 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)
  7. 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. 8. Righthumerus,anterior view
  9. 9. Righthumerus,posterior view
  10. 10. Radius is thinner proximally, like a spool Forearm 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. 11. Right forearm bones,anterior view
  12. 12. Right forearm bones,posterior view
  13. 13. In the anatomical position, the radius is Left forearm lateral (thumb side); with pronation the palm faces posteriorly and the bones cross prone Anatomical Prone: body lying face down position Suppine: body lying face up (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 theprone position and supination movesit back to the anatomical position
  14. 14. Proximal and distal joints of the forearm proximal ulna
  15. 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:
  16. 16. 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
  17. 17. Hip bone (os coxae): 3 separate bones in childhood which fuse Ilium Ischium Pubis
  18. 18. Ilium ilium Iliac crest Anterior superior iliac spine Greater sciatic notch Forms part of “acetabulum” (hip socket) ilium which receives ball-shaped head of femur
  19. 19. Ischium Body Ramus Ischial spine ischium Ischial tuberosity Part of socket ischium
  20. 20. Pubis Joins medially in pubic symphysis pubis Forms “obturator foramen” (large hole) with ischium Part of socket pubis
  21. 21. Hip bones with labels
  22. 22. False (greater) and true (lesser) pelvisLigaments
  23. 23. 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
  24. 24. Lower limb Thigh: femur Leg (lower leg)  Tibia  Fibula Foot
  25. 25. 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
  26. 26. Right femur,anterior view
  27. 27. Right femur,posterior view
  28. 28. Leg Tibia: shin bone  Medial and lateral condyles  Tibial tuberosity  Distal medial malleolus (medial ankle) Fibula  Distal lateral malleolus (lateral ankle) Interosseous membrane
  29. 29. Right lowerleg, anterior view
  30. 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. 31. Right foot, superior (dorsal) view and inferior (plantar) view
  32. 32. Right foot,lateral andmedial views
  33. 33. Arches