1512 



WRIST- JOINT (ABNORMAL ANATOMY). 



same time that the ulna has passed so far 

 downwards on the back of the carpus as to 

 reach even to the upper extremity of the 

 metacarpal bone of the little finger (see Jig. 



929.). The radius at its lowest part, besides 

 being thus shorter than the ulna, is much less 

 salient on the dorsum of the carpus. 



The upper extremity of the carpus and the 



Fig. 929, 



Second view of the same deformity as Fig. 928. 



hand are placed, as lias been mentioned, an- 

 teriorly to, and somewhat above, the lowest 

 extremity of the radius and ulna, and conse- 

 quently the measurement of the antero-pos- 

 terior diameter of the wrist is much increased ; 

 the whole forearm is somewhat bowed, pre- 

 senting on its anterior aspect a concavity in 

 the longitudinal direction. Near the wrist- 

 joint the tendons of the flexor carpi ulnaris 

 on the inner side, and of the flexor carpi ra- 

 dialis on the outer, or radial side, are thrown 

 into strong relief, and thus contribute to give 

 the quadrilateral form to the wrist above 

 alluded to. 



Since the writer made this communication 

 to the Surgical Society of Dublin, he has 

 seen other cases of congenital luxation at the 

 wrist-joint of both the bones of the forearm 

 backwards on the dorsum of the carpus. 

 They so strongly resembled the cases just 

 now adduced, that he refrains from entering 

 into particulars. From all these last men- 

 tioned, the individuals practically suffered little 

 from the defect. 



From the cases the writer has seen or in- 

 vestigated, he may draw the following conclu- 

 sions : 



1st. That the case of D. O'Neil, brought 

 before the Pathological Society of Dublin, 

 Dec. 15th, 1838, by the writer, was the first 

 example laLl before the profession with the 

 intention of proving that such a lesion as a 

 congenital luxation of the wrist-joint existed. 

 2nd. That Cruveilhier's case, adduced five 

 years previously, as a case of an old unreduced 

 luxation of the wrist-joint, and considered 

 by Dupuytren as a fracture of the radius and 

 dislocation of the ulna, and since misinter- 

 preted by others, must hereafter be looked 

 upon as an excellent example of congenital 

 luxation of both the bones of the forearm 

 backwards at the wrist-joint. 



3rd. That the case sent to Dublin by Dr. 

 MacDonnell of Montreal, is another exam- 

 ple of a congenital luxation of the bones of 

 the fore-arm at the wrist-joint backwards. 



4th. In these three the humerus and hand 

 seem to have borne, as to length and size, a 

 normal proportion to the stature of the indi- 

 viduals; but the forearms in all three were so 

 much shortened, as not to exceed by one 

 inch the measurement of the long axis of the 

 hand. 



5th. The lower extremity of the ulna in 

 the three cases, instead of being on a level 

 with the lower extremity of the radius, as it 

 normally is, had passed lower down on the 

 dorsum of the carpus from half an inch to 

 one inch. 



Besides these three cases of congenital 

 luxation of the bones of the forearm back- 

 ward at the wrist-joint, Dr. R. Smith has, in 

 his valuable work recently published, referred 

 to two more specimens of the same malform- 

 ation. A cast of one of these specimens was 

 preserved in the Museum of the Bristol In- 

 firmary, in August, 1836, when the writer and 

 Dr. Smith visited that hospital, and the bones 

 of the other specimen have been preserved 

 in the Museum of the Richmond Hospital. 



The case of O'Neil presented in her left 

 forearm the only example of which we have 

 heard of congenital luxation of the bones of 

 the forearm forwards (fig. 926.). In this case, 

 also, it is to be remarked, that the forearm was 

 preternaturally short. 



Since the above observations were written 

 I have seen other examples of congenital 

 luxations of the wrist, in which the bones of 

 the forearm were displaced backwards, and 

 the carpus forwards, as in Jigs. 92-k and 9^5. 

 Sometimes the defect was single, or only af- 

 fected one forearm ; in others, the defect, if 

 the paradoxical language be allowed, was sym- 

 metrical, affecting both wrists alike. A case 

 of this last description was shown to me 

 lately in the Downpatrick Infirmary, by the 

 surgeon of the institution, Mr. Brabazon, 

 who was kind enough to present me with a 

 cast, which 1 have in my possession.* This 

 healthy young woman is the mother of many 

 well-formed children, and feels but little in- 

 convenience from the malformation. 



When speaking of the congenital defects 

 of the elbow-joint, we noticed that the up- 

 per extremity of the radius often exceeded 

 its normal length, so as to reach as high as 

 the level of the olecranon process. (See 

 ELBOW, Abnormal Condition of.) We may 

 here remark, that the ulna as the result of 

 congenital malformation, in almost all the 

 specimens we have examined, of the congenital 



* This cast so much resembles that of fy. 920., 

 that they could scarcely be supposed to have been 

 taken from two different individuals. 



