bony pelvis is made up of hip bones, sacrum, & coccyx ... Documents/Human... · Copyright © 2006 Pearson Education, Inc., ... publishing as Benjamin Cummings C. Bones of Pelvic Girdle

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

C. Bones of the Pelvic Girdle1. 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 Girdle2. 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 Girdleb. 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 Girdle3. 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

MaleMale

Female


C. Bones of Pelvic Girdle4. 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 Limbs1. 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 Limbs2. 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 Limbb. 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 Limb3. 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 & talusi. calcaneous—heelboneii. talus—lies between tibia & calcaneous

b. 5 metatarsals: form the sole of footc. 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