Appendicular Skeleton—Lower Body
Lower Body—Pelvic Girdle
 Consists of 2 coxal bones, AKA ossa coxae or hip bones
 Boney pelvis=sacrum, coccyx, and 2 coxal bones
o Divided into two regions:
 True Pelvis—surrounded by bone and is inferior to the alae of the ilia and pelvic brim
 Dimensions of true pelvis important; must be large enough for baby to fit thru in
childbirth
 Outlet—inferior opening of pelvis, between ischial spines
 Inlet—superior opening between R and L sides of pelvic brim
 False Pelvis—superior to true pelvis, area medial to alae
 Pelvic Girdle=2 coxal bones
 Bones are large and heavy—they support most of the weight of the torso
 Bones are attached directly to axial skeleton (unlike shoulder girdles)
 Sockets that receive leg bones are deep and heavily reinforced by ligaments that attach legs to girdle
 Protect reproductive and urinary organs and some of the intestines
 Acetabulum—deep socket where Ilium, Ischium, and Pubis fuse together
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Coxal Bones (Hip Bones)
o 3 bones fused together—Ilium, ischium, and pubis
o Wing-like portions called the alae, this is where you put your hands on your hips
o Ilium
 Large, flared bones
 Articulates with sacrum at sacroiliac joint
 Iliac crest—important anatomical landmark for intramuscular injections
 Iliac crest ends in the anterior and posterior superior spine
o Ischium—“sit bones”, most inferior part of coxal bones
 Ischial tuberosity—rough area that receives weight when you sit
 Ischial Spine—important landmark in pregnant women; affects width of pelvic outlet
(thru which baby must pass thru during birth)
 Greater Sciatic Notch—allows blood vessels and sciatic nerve to pass to legs
o Pubis
 Most anterior part of coxal bone
 Obturator foramen—formed by fusion of the pubic rami and the ischium rami,
passageway for vessels and nerves to legs
 Pubic Symphysis—cartilaginous joint where pubic bones fuse anteriorly
Characteristics of Female Pelvis
 Inlet is larger and more circular
 Pelvis is shallower, bones are lighter and thinner
 Ilia flare more laterally
 Sacrum is shorter and less curved
 Ischial spines are shorter and farther apart; making outlet larger
 Pubic arch is more rounded b/c angle of arch is greater
Lower Body—Limbs
 Carry total body weight when body is upright
 Consist of thigh, leg, foot
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Thigh
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(femur bone)
Longest, heaviest, strongest bone in body
Slants medially to bring knees in line with body’s center of gravity’; more obvious in females
Proximal Features
 Head—articulates with hip bone at acetabulum in deep socket
 Neck of femur is common site of femur fractures
 Greater, lesser trocanters and gluteal tuberosity—sites of muscle attachment
 Intertrochanter line (anterior) and Intertrochanteric crest (posterior) separate
greater and lesser trochanters
o Distal Features
 Lateral and medial condyles (posterior)—articulate with tibia
 Intercondylar fossa—separates lat and med condyles
 Patellar surface (anterior) forms joint with patella
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Leg
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Foot
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Two bones—tibia (larger, medial) and fibula (lateral)
Connected by interosseous membrane
Tibia
 Proximal Features
 Lateral and Medial condyles form joint with distal end of femur to form knee joint
 Intercondylar eminence separate lat and med condyles
 Tibial Tuberosity—attaches to patellar ligament
 Distal Features
 Medial Malleolus—inner bulge of ankle
 Anterior border—sharp ridge on anterior surface of tibia, not protected by muscles,
easily palpable
Fibula
 Thin, stick-like
 Not part of knee joint
 Lateral Malleous—at distal end, forms outer part of ankle
Tarsals, metatarsals, phalanges
Support weight and act as lever to move body forward when walking/running
Bones arranged to form three arches—two longitudinal and one transverse
 Ligaments and tendons hold bones in place to maintain arches, but allow flexibility
Tarsus (tarsals)
 Posterior part of foot
 7 bones
 Body weight is carried by two largest tarsals—calcaneus (heel bone) and talus (between
tibia and calcaneus)
Metatarsals
 5 bones
 Form sole of foot
Phalanges
 14 in each foot
 3 in each toe (like hand), 2 in big (great) toe