348 APPLIED ANATOMY. 



The flaps being reflected and the hand flexed, disarticulation is begun by enter- 

 ing the knife on the ulnar side of the dorsum, beneath the styloid process. The 

 joint is followed around to the radial side, bearing in mind that it curves markedly 

 upwards. 



If the right hand is being operated on and the knife is entered transversely 

 it will strike the scaphoid bone, therefore it must be at once inclined obliquely 

 upward. Section of the flexor muscles and anterior ligament completes the disartic- 

 ulation. The radial artery will be cut in the snuff-box. The ulnar will be seen on 

 the inner side of the palmar flap, and on the outer side may be seen the superficial 

 volar. Some small branches of the anterior and posterior carpal and interosseous 

 arteries may require ligation. 



Some operators remove the styloid processes of the radius and ulna. If this is 

 done, care is to be taken not to go so high as to injure the insertion of the brachio- 

 radialis on the radius and the attachment of the triangular cartilage on the ulna. 

 Usually the styloid processes are not interfered with, in order to avoid impairing the 

 movements of pronation and supination. 



Ligation of the Radial Artery on the Dorsum of the Hand. The 

 radial artery can be ligated in the anatomical snuff-box as it crosses the back of the 



Extensor longus pollicis 



Extensor communis tendons / Extensor carpi radialis brevior 

 Extensor minimi digiti / / / Extensor carpi radialis longior 



Articular surface 

 of radius 



/~ Radial artery 







Ext. carpi ulnaris/ / / / \^ 



Triangular cartilage / / / F^&r Palmar flap 



Flexor carpi ulnaris 



Ulnar nerve Ulnar artery 



FIG. 359. Amputation through the wrist- joint of the right side. 



hand to dip between the first and second metacarpal bones and the two heads of the 

 abductor indicis muscle. The course of the artery is indicated by a line drawn from 

 the tip of the styloid process of the radius to the upper end of the first interosseous 

 space (see Fig. 348, p. 338). 



The incision is usually made in the direction of the tendons from the styloid 

 process down. As soon as the skin is divided there may be exposed in the super- 

 ficial fascia some branches of the radial nerve and the radial vein. These being 

 pushed aside, the deep fascia is opened and the artery found with its two companion 

 veins lying deep down on the external lateral ligament and trapezium. The most 

 common error in this operation is mistaking the superficial vein for the artery and 

 not searching deep enough. 



If the radial artery is wounded as it passes through the snuff-box bleeding will 

 be very free. It is almost impossible to ligate the divided ends in the wound be- 

 cause the proximal end retracts under the short extensor tendons of the thumb and 

 the distal end retracts through the first interosseous space deep into the palm of the 

 hand so that they cannot be reached. When such is the case it is necessary either 

 to ligate the ulnar and radial arteries on the anterior surface just above the wrist or, 

 as we did in one case, pack the wound with antiseptic gauze and keep the hand well 

 elevated. 



