REGION OF THE WRIST. 



345 



DISLOCATIONS AT THE WRIST. 



The dislocations at the wrist may be due to traumatism or may occur spontane- 

 ously. There may be either a displacement of the carpus at the radiocarpal joint 

 or of the ulna at the inferior radio-ulnar articulation. These luxations are very rare. 



DISLOCATIONS AT THE RADIOCARPAL JOINT. 



It is to Dupuytren that we owe the recognition of the fact that what were 

 previously regarded as luxations of the wrist were really cases of fracture, usually 

 of the radius. True luxations are exceedingly rare ; they may be either backward 

 or forward and are often compound. They are usually the result of great violence 

 and the ends of the radius and ulna in many cases protrude on the palmar or dorsal 

 surface. 



Backward luxation is the more common of the two. The question of diagnosis 

 is most important in relation to this injury. Many cases which have been diagnosed 

 as luxations afterwards prove to be fractures. In backward luxation the deformity 

 resembles that of Colics' s fracture, with the following differences : the palmar swelling 

 in dislocation extends farther down toward the hand than is the case in Colics' s 

 fracture, this is owing to the displacement occurring at the joint instead of some 

 distance above, as in fracture ; in 

 luxation the protrusion forming the 

 hump on the dorsal surface has an 

 abrupt upper edge which is lack- 

 ing in cases of fracture, and both 

 styloid processes of the radius 

 and the ulna remain attached to 

 the shaft of the bones. 



Anterior luxation may occur 

 from injury, but more commonly it 

 is seen in the form of a subluxa- 

 tion which occurs slowly and spon- 

 taneously usually between the ages 

 of 1 8 and 23 years. It was first 

 described by Dupuytren and later 



by Madelung. The ulna projects markedly toward the dorsal surface while the 

 radius is somewhat less prominent; there is a marked hollow on' the palmar surface 

 of the forearm just above the hand. Fig. 357, from a girl 18 years of age, shows 

 these points clearly. 



DISLOCATION OF THE ULNA AT THE LOWER RADIO-ULNAR JOINT. 



The ulna may be dislocated forwards or backwards. When associated with 

 fracture of the radius it is not so rare, but otherwise it is seldom seen. Posterior lux- 

 ation is the most common. The internal lateral ligament and triangular cartilage 

 both usually remain attached to the lower end of the ulna, which projects markedly 

 on the dorsal surface. The injury has been produced by falls on the hand and forced 

 pronation. 



In recent cases reduction can usually be accomplished by direct pressure and 

 rotation of the hand, with traction. The secret of success in the diagnosis of these 

 obscure fractures and luxations in the region of the wrist lies in knowing the surface 

 anatomy and in being able to recognize the various deeper structures by the sense 

 of touch. 



EXCISION OF THE WRIST. 



Formal excisions of the wrist are undertaken for tuberculous disease. It is 

 desirable that all the affected tissues be removed. To do this is difficult, on account 

 of the number and extent of the various carpal bones and joints as well as the 

 danger of injuring the important arteries, nerves, and tendons by which they are 



FIG. 357. Subluxation of the wrist from disease. 



