WRIST-JOINT (ABNORMAL ANATOMY). 



1527 



btirsa? of the extensor tendons, as they pass 

 over the carpus, also become distended : these 

 sotter fluctuating swellings after a time sub- 

 side, and the lower extremity of the radius 

 and ulna, where they enter into the formation 

 of the wrist- joint, enlarge; longitudinal ridges 

 of bone can be felt on the back of the radius 

 close to the wrist-joint. The ulna, besides 

 being much hypertrophied at its lowest point, 

 rises abnormally above the level of the dorsum 

 of the carpus. When the disease has been of 

 long duration, the region of the wrist becomes 

 contracted, the back of the carpus and hand 

 presents an attenuated appearance, showing 

 the course of the tendons, and allowing the 

 ridges and prominences of the bone to become 

 visible. 



Anatomical Characters. When we remove 

 the fibrous covering of the tendons which 

 pass by the back part of the wrist-joint and 

 carpus, we find that these tendons are gene- 

 rally deeply imbedded in bony sulci, or grooves. 

 The capsular ligament and other fibrous struc- 

 tures, both on the palmar and dorsal aspect 

 of the joint, seem to be denser and stronger 

 than natural. 



On examining the interior of the wrist- 

 joint, we notice that all the articular carti- 

 lages of encrustation have been removed frpm 

 the ends both of the radius and ulna, and 

 that the inter-articular fibre-cartilage, which 

 intervenes between the lower extremity of 

 the ulna and cuneiform bone of the carpus, is 

 removed. In general, at the usual period we 

 are afforded opportunities for making our ana- 

 tomical examinations, we find but little left of 

 the synovial membrane by which we can judge; 

 but in some cases we have found red synovial 

 fimbriae exist in the wrist-joint, just as we 

 have noticed this same vascular condition of 

 the synovial tissues to co-exist with the other 

 anatomical characters of the chronic rheu- 

 matic arthritis, as they have shown them- 

 selves in other articulations which had been 

 affected with this peculiar disease. 



Radius. The lower extremity of the radius 

 is usually somewhat enlarged, and the surface 

 of the bone is scabrous from small exostotic 

 growth. We find the grooves on the back 

 of the radius for the passage of the extensor 

 tendons are preternaturally deepened. 



The articular surface of the lower extremity 

 of the radius, where formed for the reception 

 of the summit of the carpus, is usually much 

 hollowed out, and polished from porcellanoid 

 deposition. The outline of the carpal sur- 

 face of the altered radius is usually studded 

 round with bony granules, or vegetations. 

 When we look to the ulnar side of the 

 lower extremity of the radius, we find the 

 lesser synovial cavity for the reception of 

 the carpal end of the ulna much enlarged, 

 particularly in its antero-posterior diameter. 

 This scaphoid cavity we find also presenting 

 an eburnated surface, and on it fine parallel 

 ridges and grooves are distinctly seen to run 

 in the direction of the rotation of the ulna 

 on the radius in pronation and supination. 

 Where the lower extremity of the ulna con- 



fronts the cuneiform bone (the inter-articular 

 fibro-cartilage having been removed), it pre- 

 sents a smooth and polished surface. 



Ulna. The carpal extremity of the ulna 

 is frequently much enlarged, and furnished 

 with exuberant bony growths ; its lowest ex- 

 tremity, where it confronts the cuneiform 

 bone of the carpus (without the intervention 

 of cartilage), is smooth. The part of the ex- 

 tremity destined for rotation on the radius is 

 convex, and oval from before backwards, and 

 of a form, of course, adapted to that of the 

 little scaphoid cavity in the latter, and which 

 is deprived of cartilage, eburnated, and simi- 

 larly marked with corresponding parallel ridges 

 and grooves. 



Carpus. In our anatomical investigations 

 into the state of the hands of those who have 

 long laboured under chronic rheumatic ar- 

 thritis, we have found the bones of the carpus 

 to be much altered by this disease : in general, 

 the region which these bones constitute will 

 be found to have all its dimensions contracted 

 within a smaller compass then natural. The 

 form of each individual bone is so much 

 changed, that, if found detached, it could 

 scarcely be recognised as a carpal bone. The 

 cartilaginous structure naturally intervening 

 between all the bones is always absorbed. 



Cruveilhier has said that, in the anatomi- 

 cal examination of one of his cases of this 

 disease, he found the bones of the carpus 

 confounded together into an irregular mass, 

 so that it was difficult to say the part which 

 each took in the construction of the carpal 

 region. 



On examining, anatomically, the bones of 

 the region of the wrist of a patient who had 

 been ten years labouring under this disease, 

 and was under our own immediate observation 

 for almost the whole of this period, we found 

 the bones of the carpus were exceedingly 

 rough on their non-articular surfaces ; each 

 individual bone was found much altered from 

 its normal figure; some were enlarged beyond 

 their usual size, others diminished : the true 

 annular ligament of the carpus, which con- 

 nected the small bones together on their 

 palmar aspect, and contributed to maintain 

 the arched form of this region, was much 

 shorter than usual. 



When we examined each bone, we found 

 that the scaphoid was eburnated on its su- 

 perior articular surface, where it corresponded 

 to a similar surface on the carpal end of the 

 radius. Below, the scaphoid, instead of con- 

 tributing, with the head of the os magnum, to 

 form part of the medio-carpal articulation, 

 was really united to the head of the os mag- 

 num by true bony anchylosis. The semi- 

 lunar and cuneiform of the first range were 

 much enlarged. The os lunare, where, by its 

 lower concave surface, it corresponded to 

 half of the head of the magnum, was not, like 

 the scaphoid, united to this last bone, but, on 

 the contrary, both surfaces of the magnum 



* Vide a work on Chronic Rheumatic Arthritis, 

 by the author, shortly to be published. 



5 E 4 



