288 SKELETON. 



essentially upon the muscles which surround it, as the deltoid, 

 supra-spinatus, infra-spinatus, teres minor, sub-scapularis, long 

 head of triceps, and some others, which are farther removed 

 from it. 



The synovial membrane is a perfect sac, which covers the 

 glenoid cavity, the internal face of the capsular ligament, and 

 the neck and head of the os humeri. On the lower part of the 

 neck it is reflected over some small fatty masses, commonly called 

 glands. Just beneath the root of the coracoid process, from there 

 being a deficiency of the capsular ligament, the synovial mem- 

 brane covers the articular side of the tendon of the sub-scapu- 

 laris, and is reflected for ten or twelve lines, between it and the 

 scapula, forming a sort of pouch, resembling a bursa mucosa. 



The tendon of the biceps muscle runs through this articulation 

 from the superior end of the glenoid cavity. The cavity itself is 

 deepened by a fibrous margin all around, called the glenoid liga- 

 ment; a considerable part of whose fibres may be traced from 

 the tendon of the biceps by its bifurcating. The tendon is bound 

 down in the bicipital -groove by fibres passing from one to the 

 other of the bony margins, and which may be considered a 

 continuation of the capsular ligament. As the tendon is about 

 emerging from the groove at the lower margin of the tuberosi- 

 ties, the synovial membrane which lines the groove thus far, is 

 reflected from it, to the surface of the tendon, and continues to 

 cover and enclose it up to the origin at the glenoid cavity. It is 

 thus evident that though the tendon passes through the joint, 

 the cavity of the synovial membrane is kept entire. 



Of the Elbow Joint. 



This articulation is formed by the lower end of the os hu- 

 meri and the upper end of the ulna and of the radius. The ar- 

 ticular faces which were described in the account of these 

 bones are covered, as usual, with cartilage, the particular ar- 

 rangement of which will be presently pointed out. A strong 

 capsular ligament, an annular or coronary ligament, and a syno- 

 vial membrane, hold these several bones together. 



The Capsular Ligament invests completely the articular ex- 



