BONES AND MUSCLES OF THE FOOT. 



487 



than those of the carpus, and some of them of considerable 

 size. The articulation with the leg is formed by one of these 

 only, the astragalus, which projects above the rest, and is im- 

 bedded between the projecting extremity of the tibia (which 

 forms the inner boundary of the ankle-joint) and that of the 

 fibula. The astragalus rests on the os calcis or bone of the 

 heel, which projects considera- 

 bly backwards, and is connected 

 in front with the other bones of 

 the tarsus. In front of the 

 tarsus we find the metatarsus, 

 composed of five long bones, 

 which in man are all attached 

 to each other, but of which one 

 is separate in the Quadrumana, 

 in order to give freer play to 

 the great toe, the action of which 

 resembles that of the thumb. 

 The toes, like the fingers, are 

 composed of three phalanges 

 (with the exception of the 

 great toe, which has only two) ; 

 these are in Man much shorter 

 than those of the hand, and 

 are evidently not adapted for 

 prehension but in many of the 

 Quadrumana, their length is 

 nearly equal to that of the 

 fingers, and the great toe is as 

 opposable as the thumb. The 

 foot is far from being thus con- 

 verted, however, into a perfect 

 hand ; but it becomes a very 

 useful instrument for clasping 

 the small branches and twigs 

 of the trees among which these 

 animals live. The foot of Man 

 is distinguished from theirs, by 

 its power of being planted flat upon the ground, and thus 

 affording a firm basis of support. Even the Chimpanzee 

 and the Orang, when they attempt to walk erect, rest upon 



Fig. 230, MUSCLES OF THE SOLE OF 



THE FOOT (MIDDLE LAYER). 



1, accessory of the long flexor of the 

 toes ; 2, tendon of the long flexor 

 issuing from its sheath ; 3, tendon 

 of the long flexor of the great toe; 

 4, first lumbricalis ; 5, tendon of 

 the superficial flexor, divided be- 

 hind its perforation ; 6, short flexor 

 of the little toe ; 7, short flexor of the 

 great toe; 8, portion of the oblique 

 abductor of the great toe ; 9, poste- 

 rior extremity of the fifth metatar- 

 sal bone ; 10, sheath of the long pero- 

 neal; 11, os calcis, or bone of the 

 heel. 



