ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 



586 



The capsular ligament is occasionally in- 

 creased in thickness, and its fibres are hyper- 

 trophied ; and it is generally more capacious 

 than natural, showing that effusion of synovia 

 to a considerable amount had existed, although 

 the external signs of this phenomenon are not 

 usually evident. When the interior of the 

 synovial sac is examined, it will be found to 

 present evidences of having been the seat of 

 chronic inflammation. Bunches of long or- 

 ganised fringes hang into the interior of the 

 synovial sac; and many of these vascular 

 fimbriae, which in the recent state are of an 

 extremely red colour, surround the corona of 

 the head of the humerus. We also notice 

 rounded cartilaginous productions, appended 

 by means of membranous threads attached to 

 the interior of the various structures which 

 compose the joint. Some of these foreign 

 bodies are small, others large. Some are 

 round ; but their shapes are various. Besides 

 these rounded cartilaginous bodies, we occa- 

 sionally find osseous productions of a mul- 

 tangular form added to the edges of the gle- 

 noid cavity, deepening it, and increasing the 

 articular surface for the reception of the head 

 of the humerus, which usually is in such 

 cases much enlarged. 



The intra-articular part of the long tendon of 

 the biceps is very seldom to be seen in the 

 interior of the joint ; but immediately out- 

 side of the capsular ligament the latter tendon 

 will generally be found to have contracted a 

 firm adhesion to the superior extremity of 

 the bicipital groove (./% 428. a.). 



Bones. The head of the humerus assumes 

 a very characteristic appearance as a con- 

 sequence of this peculiar disease, and acquires 

 a form which cannot be easily mistaken for 

 the effects of any other disease or accident. 

 The usual angle at which the head and neck 

 of the humerus join the shaft of the bone is 

 often altogether effaced ; so that instead of the 

 axis of the head and neck of the humerus 

 being directed, as it normally is, upwards, 

 inwards, and backwards, it seems to run ver- 

 tically, or, as it were, in a continuous line 

 with* that of the shaft of the bone. The 

 articular surface is usually much enlarged, 

 and in the ordinary form of this disease occu- 

 pies the whole summit of the humerus, ex- 

 tending itself even over the greater and lesser 

 tuberosities and the highest part of the bi- 

 cipital groove ; effacing in this direction part 

 of the circular line which marks the anato- 

 mical neck of the humerus and insertion of 

 the capsular ligaments. Some of the articular 

 cartilage is removed from the head of the 

 bone, which, in some places, presents a porous 

 appearance (j%. 428.). 



In other parts, in place of the cartilage, 

 there is a polished ivory-like surface. The 

 portion of the bone which thus presents this 

 polished surface is the very summit of the 

 humerus ; and this is the part of the bone 

 which will be found evidently to have been 

 for years in habitual contact with the under 

 surface of the acromion and coracoid pro- 

 cess, where these bones assist in forming ppr- 



tions of the new and abnormal cavity for the 



reception of the head of the humerus. The 



Fig. 428. 



Chronic rheumatic arthritis : a, tendon of the biceps 



basis of the head, in the line where it joins 

 the shaft of the humerus, is studded round by 

 granular osseous productions, which give to 

 it a characteristic appearance (Jig- 428.). By 

 these vegetations of bone, we are reminded of 

 the analogous appearance which the corona of 

 the head of the femur presents when affected 

 by the same species of morbid action *; but of 

 course much variety may be expected to be 

 found in the form the head of the humerus will 

 assume under the influence of this disease : we 

 have found the articular surface in soine cases 

 formed completely on the summit of the hu- 

 merus, sometimes on the side of the head. 

 Very generally the head of this bone is much 

 enlarged, but exceptions to this rule occur. 

 One of the most remarkable alterations of 

 form we have noticed as the result (as we 

 imagine) of this disease we found in the 

 anatomical museum at Leyden. In the spe- 

 cimen to which we allude, the head of the 

 humerus appears bifurcated at its upper part, 

 or divided longitudinally into two surfaces 

 for articulation with the scapula.f 



Lastly, we have to advert to the anatomi- 

 cal characters of the new and abnormal socket 

 formed for the reception of the altered head 

 of the humerus. This new cavity is com- 

 posed of two portions, which however will be 

 found to have become almost continuous with 

 each other. The original glenoid cavity (ge- 

 nerally much enlarged) forms one of these 

 portions ; the coraco-acromial vault the other. 



* Vol. II. fig. 317. page 802. 



f Sandifort in his fourth volume has given a 

 delineation of the head of the humerus in this 

 case as well as of the scapula the glenoid cavity of 

 which was enlarged very much in the direction 

 downwards, and \vas surrounded with a margin of 

 osseous granules. 



