146 ADAPTATION OF SKELETON TO ERECT ATTITUDE. 



balance of the body is principally preserved. The hip-bone is mainly distinguished from the 

 same bone in animals by the breadth of its iliac portion, which gives support to the abdominal 

 viscera, and attachment to the greatly developed iliac and gluteal muscles. 



The lower limbs are remarkable for their length and strength. The femur is greatly 

 elongated, its length considerably exceeding that of the tibia, a condition which is requisite 

 not only to give a sufficient extent of stride, but also to enable the body to be balanced in dif- 

 ferent degrees and varieties of stooping. The foot of man alone among animals has an arched 

 instep, and it likewise presents a great breadth of sole. The great toe is distinguished by its 

 full development, and especially from that of the apes, by its want of opposability, 

 being constructed, not for grasping, but for supporting the weight of the body, and giving 

 spring to the step. 



While stability and strength are thus provided in the lower limbs, mobility and lightness 

 are secured in the upper. This is apparent on comparison of the shoulder, elbow, and wrist, 

 with the hip, knee, and ankle. In the hand, also, the freely moveable phalanges are as long 

 as the carpal and metacarpal bones taken together, while in the foot they are not a third of 

 the length of the tarsal and metatarsal bones. 



