158 SURGICAL ANATOMY OF THE REGION 



especially the palmaris longus and flexor carpi radialis ; 

 the posterior, in extension of the wrist or fingers, and in 

 extension of the thumb. The position of the styloid pro- 

 cesses of the radius and ulna can be felt, the former 

 lower down than the latter; the relation of these pro- 

 cesses, however, is altered during pronation and supina- 

 tion. In front of the styloid process of the radius is the 

 root of the thumb and prominence of the scaphoid, and 

 on the inner side is the pisiform bone, with the. flexor 

 carpi ulnaris attached to it. The pulsations of the 

 radial and ulnar arteries can be easily felt and gener- 

 ally seen ; the former on the radial side of the flexor 

 carpi radialis ; the latter on the radial side of the flexor 

 carpi ulnaris. 



Dissection. On reflecting the skin, the subcutaneous 

 cellular tissue is seen, free from fat, and lying in it are 

 the cutaneous vessels, nerves, and lymphatics. The 

 aponeurosis is a continuation of that forming the sheath 

 of the muscles of the forearm, which is remarkable at 

 the wrist as being very strong, and affording special 

 channels for the passage of the tendons of the muscles 

 of the forearm. It consists of two portions an ante- 

 rior, very thick and strong (anterior annular ligament), 

 continuous with the deep fascia of the forearm, which is 

 attached to the pisiform, unciform, radius, scaphoid and 

 trapezium bones, receiving an expansion of the tendon of 

 the palmaris longus, and forming an arch between the 

 thenar and hypothenar regions ; and a posterior, dense, 

 and formed of circular and longitudinal bundles of tissue 

 attached to the ulna, cuneiform, pisiform bones, to the 

 radius, and to the several eminences on its dorsal aspect, 

 which separate the extensor tendons, and is thus divided 



