THE FOREARM AND WRIST. 65 



the more manifest by being covered by the first two extensor 

 tendons of the thumb. It descends lower, and lies more to 

 the front than the corresponding process of the ulna. The 

 relative positions of these styloid processes can be best 

 examined by placing the thumb on one and the forefinger on 

 the other. 



Feel for the little bony pulley on the back of the radius 

 near the wrist, which keeps in place the third extensor tendon 

 of the thumb. This and the bone just above it is the place 

 which we examine for a suspected fracture (termed Colles's) 

 near the lower end of the radius. 



141. Carpus. Below the styloid process of the radius, 

 just on the inner side of the extensors of the thumb, we feel 

 the tubercle of the scaphoid bone. Between the styloid pro- 

 cess and the tubercle is the level of the radio-carpal joint. 

 A little lower we feel the trapezium. 



Just below the ulna on the palm of the hand we feel the 

 pisiform bone ; and on the inner side of this, the cuneiform. 



There are several transverse furrows on the palmar aspect 

 of the wrist. The lowest of these, which is slightly convex 

 downwards, corresponds with the upper edge of the anterior 

 annular ligament and the intercarpal joint. The line of the 

 radio-carpal joint, as already stated, is on a level with the 

 apex of the styloid process of the ulna. 



In forcible flexion of the wrist, the tendon of the flexor 

 carpi radialis and that of the palmaris longus come up in 

 relief. On the outer side of the first-named tendon we feel 

 the pulse, the radial artery here lying close to the radius. 



The tendon of the palmaris longus runs near the middle 

 of the wrist, and close to its inner border runs the median 

 nerve. In letting out deep-seated matter near the wrist, the 

 incision should be made close to and parallel with the inner 

 edge of the radial flexor tendon, so as to avoid injury to the 

 median nerve. 



We can feel the tendon of the flexor carpi ulnaris for 

 some distance above the wrist. It overlies the ulnar artery, 

 and somewhat masks its pulsation. 



142. Pulse. The ' pulse at the wrist ' is felt just outside 



F 



