636 MAN xxiv. 7- 



and the flexor muscles of the elbow, wrist, and hand are all much 

 larger in apes, as are the ridges to which they are attached, for instance 

 on the palmar surfaces of the phalanges (Fig. 411). The human 

 arm has specialized in mobility. The hand can be brought into almost 

 any position in relation to the body by virtue of the wide range of 



Homo Cap - Gorilla 



Fig. 411. Bones of the left hands of man and gorilla, palmar view. 



cap. capitate; h. hamate; /. lunate; mc. metacarpal; />. pisiform; sc. scaphoid; t. trapezium; 

 tr. triquetral; tz. trapezoid. 



Notice the large bony points of attachment of the flexor muscles of the gorilla on the trapez- 

 ium, scaphoid, hamate, and proximal phalanges. 



movement at the shoulder, pronation and supination of the forearm 

 and movements at the wrist. 



In the hand itself the thumb is characteristically long in man and 

 moved by powerful muscles. Man is the only animal in which the 

 thumb can be in the fullest sense opposed to the other digits, so that 

 the pads face each other. This is achieved by special development 

 of the joint between the first carpal and metacarpal. The third digit 

 is the longest in apes, as in men, but the second digit (index) of man is 

 generally at least as long as the fourth, often longer (the 'Napoleonic 



