THE ILIUM 93 



It is interesting that the corresponding metatarsals articu- 

 late with exactly the same number of bones of the tarsus. 



THE BONES OF THE LOWER EXTREMITY 



The lower limb consists of the haunch, or hip, thigh, leg, 

 and foot. In the haunch is the hip bone; in the thigh, the 

 femur; in the leg, the tibia and fibula; at the knee, a large 

 sesamoid bone, the patella; in the foot, the tarsus, metatarsus, 

 and phalanges. 



THE BONES OF THE PELVIS (PELVIC GIRDLE) 



The Hip Bones (Ossa Innominata) 



The hip or innominate bone (os coxce), with its fellow, the 

 sacrum, and coccyx form the pelvis. This bone is constricted 

 in the middle and expanded above and below. In early life 

 it is made up of three bones, the ilium, pubes, and ischium, 

 and for the sake of description the adult bone is said to be 

 made up of these portions. 



The Ilium 



The ilium (ilium, flank) is the superior expanded portion, and 

 forms less than two-fifths of the acetabulum. This portion is 

 limited anteriorly and posteriorly by margins which diverge at 

 right angles from each other, and superiorly by the arched crest 

 of the ilium. In front the crest is concave inward, and behind 

 it is concave outward. It is much wider near its extremities 

 than in its middle, and there is often a marked external projec- 

 tion in its anterior third. On the crest are external and internal 

 lips and a median ridge. 



The anterior extremity projects as the anterior superior spine; 

 below it is a concavity, the lesser iliac notch, and below that 

 the anterior inferior spine. Behind, the projecting extremity 

 of the crest is called the posterior superior spine, separated by 

 a small notch from the posterior inferior spine, below which is 

 the great sciatic (iliosciatic) notch. 



