appendicular skeleton

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  • 1. The Appendicular Skeleton

2. The Appendicular Skeleton Pectoral girdle attaches the upper limbs to thetrunk Pelvic girdle attaches the lower limbs to the trunk Upper and lower limbs differ in function sharethe same structural plan 3. The Pectoral Girdle Consists of the clavicle and the scapula Pectoral girdles do not quite encircle the bodycompletely Medial end of each clavicle articulates with themanubrium and first rib Laterally the ends of the clavicles join thescapulae Scapulae do not join each other or the axialskeleton 4. The Pectoral Girdle Provides attachment for many muscles that movethe upper limb Girdle is very light and upper limbs are mobile Only clavicle articulates with the axial skeleton Socket of the shoulder joint (glenoid cavity) isshallow Good for flexibility bad for stability 5. Articulated Pectoral Girdle 6. Clavicles Extend horizontallyacross the superiorthorax Sternal endarticulates with themanubrium Acromial endarticulates withscapula 7. Clavicles Provide attachment for muscles Hold the scapulae and arms laterally Transmit compression forces from the upper limbsto the axial skeleton 8. Scapulae Lie on the dorsal surface of the rib cage Located between ribs 2-7 Have three borders Superior, medial (vertebral), and lateral (axillary) Have three angles Lateral, superior, and inferior 9. Structures of the Scapula 10. Structures of the Scapula 11. Structures of the Humerus of the Right Arm 12. Forearm Radius and ulna articulate with each other At the proximal and distal radioulnar joints Interconnected by a ligament the interosseousmembrane In anatomical position, the radius is lateral and theulna is medial 13. Details of Arm and Forearm 14. Ulna Main bone responsible for forming the elbow jointwith the humerus Hinge joint allows forearm to bend on arm Distal end is separated from carpals byfibrocartilage Plays little to no role in hand movement 15. Proximal Part of the Ulna 16. Radius and Ulna 17. Radius Superior surface of the head of the radiusarticulates with the capitulum Medially the head of the radius articulates withthe radial notch of the ulna Contributes heavily to the wrist joint Distal radius articulates with carpal bones When radius moves, the hand moves with it 18. Distal Ends of the Radius and Ulna 19. Hand Includes the following bones Carpus wrist Forms the true wrist the proximal region of thehand Gliding movements occur between carpals Composed of eight marble-sized bones Metacarpals palm Phalanges fingers 20. Bones of the Hand 21. Pelvic Girdle Attaches lower limbs to the spine Supports visceral organs Attaches to the axial skeleton by strong ligaments Acetabulum is a deep cup that holds the head ofthe femur Lower limbs have less freedom of movement Are more stable than the arm 22. Pelvic Girdle Consists of paired hip bones (coxal bones) Hip bones unite anteriorly with each other Articulates posteriorly with the sacrum Bony Pelvis A deep, basin-like structure Formed by coxal bones, sacrum, and coccyx 23. Bony PelvisFigure 8.7a 24. Lateral and Medial Views of the Hip Bone 25. True and False Pelves Bony pelvis is divided into two regions False (greater) pelvis bounded by alae of the iliacbones True (lesser) pelvis inferior to pelvic brim Forms a bowl containing the pelvic organs 26. True and False Pelves 27. Pelvic Structures and Childbearing Major differences between male and female pelves Female pelvis is adapted for childbearing Pelvis is lighter, wider, and shallower than in themale Provides more room in the true pelvis 28. Female and Male Pelves 29. Female and Male Pelves 30. Thigh The region of the lower limb between the hip andthe knee Femur the single bone of the thigh Longest and strongest bone of the body Ball-shaped head articulates with the acetabulum 31. Structures of the Femur 32. Patella Triangular sesamoid bone Imbedded in the tendon that secures thequadriceps muscles Protects the knee anteriorly Improves leverage of the thigh muscles across theknee 33. Structures of the Tibia and Fibula 34. The Foot Foot is composed of: Tarsus, metatarsus, and the phalanges Important functions Supports body weight Acts as a lever to propel body forward whenwalking Segmentation makes foot pliable and adapted touneven ground 35. Tarsus Makes up the posterior half of the foot Contains seven bones called tarsals Body weight is primarily borne by the talus andcalcaneus 36. Metatarsus Consists of five small long bones calledmetatarsals Numbered 15 beginning with the hallux(great toe) First metatarsal supports body weight 37. Phalanges of the Toes 14 phalanges of the toes Smaller and less nimble than those of the fingers Structure and arrangement are similar to phalangesof fingers Except for the great toe, each toe has threephalanges Proximal, middle, and distal 38. Bones of the Foot 39. Bones of the Foot 40. Arches of the Foot Foot has three important arches Medial and lateral longitudinal arch Transverse arch Arches are maintained by: Interlocking shapes of tarsals Ligaments and tendons 41. Arches of the Foot 42. Disorders of the Appendicular Skeleton Bone fractures Hip dysplasia head of the femur slips out ofacetabulum Clubfoot soles of the feet turn medially 43. The Appendicular Skeleton Throughout Life Growth of the appendicular skeleton Increases height Changes body proportions Upper-lower body ratio changes with age At birth head and trunk are 1.5 times as long aslower limbs Lower limbs grow faster than the trunk Upper-lower body ratio of 1 to 1 by about age 10