TRANSACTIONS OF SECTION H. 779 



all the toes a powerful grasping organ is produced, more important even than its 

 hand, in which the thumb is feebly developed. 



It has sometimes been assumed that the human foot is also a prehensile instru- 

 ment as well as an organ of support. In a limited sense objects can undoubtedly 

 be grasped by the human toes when bent towards the sole. In savages, this power 

 is preserved to an extent which is not possible in civilised man, in whom, owing 

 to the cramping, and only too frequently the distorting influence, exercised by 

 badly fitting boots and shoes, the proper development of the functional uses of the 

 toes is impeded and their power of independent movement is often destroyed. 



Even in savages who have never worn shoes, the power of grasping objects by 

 the toes cannot be regarded as approximately equal in functional activity and 

 usefulness to the range of movement possessed by the ape. The four outer toes 

 are so short and comparatively feeble, that they cannot encircle an object of any 

 magnitude. But, what is even more important, the great toe cannot be opposed to 

 the surface of the sole, in the way that an ape can move its hallux or a man his 

 thumb. Savage man can no doubt pick up an object from the ground with the 

 great toe. Many of us have doubtless seen, among civilised men, persons who have 

 had the misfortune to be born without arms, or who have accidentally lost them 

 in early life, who have trained themselves to hold a pen, pencil, brush, or razor 

 with the foot, and to write, draw, paint, or even shave. But in these cases the 

 object is held between the hallux and the toe lying next to it, and not grasped 

 between the great toe and the sole of the foot by a movement of opposition. 



If we compare the anatomical structure of the human foot with that of the foot 

 of the ape, though the bones, joints, and muscles are essentially the same in both, 

 important differences in arrangement may be easily recognised, the value of which 

 will be better appreciated by first glancing at the thumb. Both in man and apes 

 the thumb is not tied to the index digit by an intermediate ligament, which, under 

 the name of ' transverse metacarpal,' binds all the fingers together, and restricts 

 their separation from each other in the transverse plane of the hand. The great 

 toe of the ape, similarly, is not tied to the second toe by a ' transverse metatarsal 

 ligament,' such as connects together and restricts the movements of its four outer 

 toes in the transverse plane of the foot. The hallux of the ape is therefore set 

 free. _ It can, like the thumb of man and ape, be thrown into the position of 

 opposition and be used as a prehensile digit. Very different is the case in the 

 human foot, in which the hallux is tied to the second toe by a continuation of the 

 same transverse metatarsal ligament which ties the smaller toes together. Hence 

 it is impossible to oppose the great toe to the surface of the sole in the way in 

 which the thumb can be used, and the movements of the digit in the transverse 

 plane of the foot are also greatly restricted. 



The development of a connecting transverse band, for the restriction of the 

 movements of tiie great toe in man, is not the only anatomical structure which 

 differentiates it from the hallux of an ape, or the thumb in the hand. In the 

 manus both of man and apes the joint between the metacarpal bone of the thumb 

 and the bone of the wrist (trapezium) is concavo-convex, or saddle-shaped, and 

 permits of a considerable range of movement in certain directions, and notably the 

 movement of opposition. A joint of a similar configuration, permitting similar 

 movements, is found in the pes of the ape between the metatarsal of the hallux and 

 the tarsal bone with which it articulates. In the foot of man, on the other hand, 

 the corresponding joint is not saddle-shaped, but is almost plane-surfaced, and con- 

 sequently the range of movement is slight, and is little more than the gliding of 

 one articular surface on the other. 



One of the chief factors in the production of the movement of opposition in the 

 manus of man and apes is a special muscle, the opponens poUicis, which, through 

 its insertion into the shaft of the metacarpal bone of the thumb, draws the entire 

 digit across the surface of the palm. In the foot of the Anthropoid apes there is 

 not complete correspondence in different species in the arrangement of the muscles 

 which move the great toe. In the Orang the abductor hallucis, in addition to the 

 customary insertion into the phalanx, may give rise to two slips, one of which is 

 inserted into the base and proximal part of the first metatarsal bone, and the other 



