C. Bones of the Pelvic Girdle 1. 2 coxal bones (a.k.a hip bones): -bony pelvis is made up of hip bones, sacrum, & coccyx -pelvic bones are large & heavy & attach to the axial skeleton via sacrum/coccyx -The total weight of the upper body rests on the pelvis -Protects reproductive organs, urinary bladder, & part of large intestine
The Pelvis Figure 5.23a
C. Bones of Pelvic Girdle 2. Fusion of 3 bones to form each coxae a. ilium: large, flaring bone that forms most of hip bone; it is the most superior of hip bones *sacroiliac joint where ilium connects with sacrum posteriorly *iliac crest upper edge of ilium (along superior margin); hands on hips indicates placing hands on iliac crest
C. Bones of Pelvic Girdle b. ischium: forms the most inferior part of the coxal bone; known as the sit-down bone c. pubis (pubic bone): the most anterior part of a coxal bone *obturator foramen an opening that allows blood vessels & nerves to pass into anterior part of thigh *pubic symphysis pubic bones of each hip bone fuse anteriorly to form this cartilaginous joint *acetabulum receives the head of the thigh bone; location where ilium, ischium, & pubis fuse at deep socket
The Pelvis: Right Coxal Bone Figure 5.23b
C. Bones of Pelvic Girdle 3. False & True pelvis: the true pelvis is surrounded by bone, lies inferior to flaring parts of ilia and pelvic brim *Woman s true pelvis must be large enough to allow infant s head (largest part of infant) to pass during childbirth Male Female
C. Bones of Pelvic Girdle 4. 6 differences between male & female pelvis 1. female inlet is LARGER & more circular 2. female pelvis as whole is shallower, and bones are lighter and thinner 3. female ilia flare more laterally 4. female sacrum is shorter & less curved 5. female ischial spines are shorter & farther apart; thus outlet is LARGER 6. female pubic arch is more rounded b/c angle of pubic arch is greater
D. Bones of the Lower Limbs Lower limbs carry our total body weight when we are erect Lower limb bones therefore are much thicker & stronger than upper limb bones Lower limbs have 3 segments thigh, leg, foot Figure 5.24a b
D. Bones of Lower Limbs 1. Thigh has only one bone a. femur: the thigh bone is the heaviest, strongest bone in body -on proximal end, has a ball-like head, a neck, and greater/lesser trochanters -head of femur fits into acetabulum of hip bone to form hip joint
D. Bones of Lower Limbs (a. femur continued) *lateral/medial condyles projections that articulate with tibia bone below; located on distal end of femur
D. Bones of Lower Limbs 2. Leg: 2 bones form the skeleton of the leg a. tibia: shinbone -larger & more medial *lateral/medial condyles located at proximal end of tibia; articulate with distal end of femur to form knee joint *medial malleolus located at distal end of tibia, forms the inner bulge of ankle *anterior border sharp ridge on anterior surface of tibia, unprotected by muscles so is felt easily beneath the skin
D. Bones of Lower Limb b. fibula: lies alongside tibia and is think and sticklike -has NO part in forming knee joint *lateral malleolus at distal end of fibula & forms outer part of ankle
D. Bones of Lower Limb 3. Foot composed of tarsals, metatarsals, & phalanges. -2 important functions: supports body weight & serves as lever that allows us to propel our bodies forward when we walk/run a. tarsals: 7 ankle bones (see fig. 5.25)
D. Bones of Lower Limb (a. tarsal bones continued) **body weight is mostly carried by the 2 largest tarsals calcaneous & talus i. calcaneous heelbone ii. talus lies between tibia & calcaneous b. 5 metatarsals: form the sole of foot c. phalanges: 14 bones that form the toes * toes each toe has 3 phalanges (proximal, middle, distal) except the great toe * great toe has only 2 phalanges (proximal & distal)
D. Bones of Lower Limbs d. 3 arches of foot: Bones of the foot are arranged to form three strong arches Two longitudinal One transverse Ligaments & tendons help to hold bones firmly in arched position Figure 5.26