4 THE SUPERIOR EXTREMITY 



Just lateral to the styloid process and slightly proximal to 

 it there is a rounded piece of bone called the head of the ulna. 

 It is best seen and felt when the palm of the hand is turned 

 downwards. 



The radius is more deeply buried than the ulna, but there 

 is no difficulty in locating its proximal and distal ends. The 

 proximal end, called the head of the radius, lies a short distance 

 distal to the lateral epicondyle of the humerus. Its position 

 is marked on the back of the forearm by a dimple of the 

 skin. If a finger is placed in the dimple the head of the 

 radius can be felt rotating when the palm of the hand is 

 turned alternately upwards and downwards. 



The distal end of the radius is the quadrangular mass of 

 bone which can be felt at the lateral side and the back of the 

 wrist. It lies lateral to the head of the ulna and it terminates 

 on the lateral side in a pointed process, the styloid process of 

 the radius. 



The eight carpal bones of the wrist lie in the interval 

 between the styloid processes of the radius and ulna, beyond 

 which they extend distally for a short distance (Figs. 3, 67, 77). 



The^fod metacarpal bones of the hand, one for each digit, 

 extend from the carpus to the phalanges. 



They are numbered one to five from the thumb to the 

 little finger side, and all are easily felt at the back of the 

 hand, where the heads or distal ends form the prominences 

 known as the "knuckles." 



The fourteen phalanges are in the free parts of the digits: 

 two in the thumb, first or proximal and second or distal ; 

 three in each finger, proximal or first, middle or second, and 

 distal or third. The second phalanx of the thumb and the 

 third phalanges of the fingers are frequently called terminal 

 phalanges. 



The structures connected and associated with all the 

 bones mentioned have to be examined by the dissector of 

 the superior extremity, and whilst waiting to commence the 

 dissection the dissector should verify all the points above 

 mentioned upon his own body with the aid of his fingers and 

 a looking-glass. 



Since many students commence dissecting before they 

 have attended either lectures or demonstrations on Anatomy, 

 they are unacquainted with terms which must be used in the 

 instructions given regarding the dissections which are to be 





