CONGENITAL. -,- Congenital dislocation of the bones which constitute the radio-carpal articulation may be considered rare; never theless, I have seen within these few years thirteen examples of this malformation. One, in which the bones of the forearm were thrown forwards and the carpus backwards. In the remaining twelve cases, the bones of the forearm were placed on the dorsuin of the carpus, which they overlapped.
The history of congenital luxations of the wrist-joint is modern. Cruveilhier, in his Pathological Anatomy (liv. ix., 1833), has published an example of this deformity, al though he was not himself aware of the true nature of the case. The example he adduces is that of an adult female, concerning whose history, unfortunately, he could learn nothing. In this case the forearm was preternaturally short, and it formed a right-angle with the hand, which besides was inclined to the radial side of the forearm; extension was im possible; flexion, to a certain degree, was per mitted ; the inferior extremities of the radius and ulna were dislocated backwards, and formed a very considerable prominence be neath the skin posteriorly.
The extremity of the radius was less salient, and descended much less than that of the ulna. The superior extremity of the carpus could be felt on a plane which was superior and ante rior to that of the inferior extremity of the bones of the forearm.
Dis,ieetion.— The bones of the carpus were found on dissection to be in a state of atrophy, and more or less malformed ; the radius, short ened and deformed, scarcely measured five inches; the deformity principally affected its lower extremity, which was large and deeply grooved posteriorly for the reception of the tendons of the extensor muscles; the articular surface for the carpus was placed on the an tenor aspect of the bone; the ulna was only six inches and a half in length, its lower ex• tremity, much smaller than normal, descended half an inch below the carpal extremity of the radius.
The carpus was much deformed, particu larly as to the first row, which was merely, we may say, in a rudimentary state. The pisi form was the only bone of this first range that was normal. The bones of the second or metacarpal row participated in the deformity. The head of the os magnum was altogether absent, and the unciform was imperfect.
Cruveilhier published the foregoing case, erroneously supposing it an example of dislo cation of the wrist-joint, the result of accident. Dupuytren and Marjolin disagreed with Cru veilhier, but equally mistook the true nature of this case ; they, doubting the possibility of an accidental luxation of the wrist-joint, con sidered that all the phenomena which the post-mortem examination of the limb presented in Cruveilhier's example, might be accounted for by supposing the case to have been one of fracture of the radius, and consecutive dis placement of the ulna.
It must ever appear as a matter of surprise that Cruveilhier could have supposed that this case just adduced was an old accidental luxa tion left unreduced, because, according to such an hypothesis, neither the arrest of develop ment as to the length of the forearm (which only measured six inches and a half), nor the abnormal appearances observed in the bones of the carpus, could have been satisfactorily accounted for, or explained.
It is equally difficult to imagine how it was that Dupuytren, who had his attention so much alive to the subject of congenital luxa tions, should have overlooked the true nature of Cruveilhier's case, and referred the pheno mena it presented to the circumstance of the radius having been broken through its lower epiphysis; no one ever heard of shortening of the radius to this amount as the result of frac ture ; besides, the bones on the carpus were in a state of atrophy, and the ulna, which Du puytren did not suppose had been fractured, was deformed, and only six inches and a half long.