618 



ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 



also slightly adductecl towards the middle 

 line. When the shoulder is viewed posteriorly 

 a depression corresponding to the situation 

 of the posterior half of the glenoid cavity is 

 observable : into this depression the ringer can 

 be sunk so far as to reach the surface of the 

 posterior part of the glenoid cavity. When 

 the arm is drawn forwards across the chest, 



the head of the humerus passes backwards 

 beneath the acromion, and a depression can 

 be felt in front beneath the coracoid process, 

 corresponding to the portion of the abnormal 

 articular cavity which the head of the humerus 

 had just before occupied. The muscles of the 

 region of the shoulder are very imperfectly 

 developed, but those of the fore-arm and 



Fie. 441. 



Case of M. H. Congenital malformation of the left shoulder joint, with luxation of the head of the 



humerus inwards. 



hand seem of their normal size. The patient 

 has but little power of moving the affected 

 upper extremity. The trapezius muscle of 

 this side is well formed, therefore he can by 

 means of its influence elevate on the side of 

 the trunk the whole limb. The deltoid and 

 capsular muscles are very imperfectly formed, 

 and consequently the patient has no power 

 of abduction, nor of rotation, of the humerus. 

 The shoulder has not the usual rounded form, 

 but still it does not present the flattened ap- 

 pearance, nor the acromion the angular out- 

 line which characterises the accidental luxa- 

 tion of this joint. Yet the acromion process 

 does project somewhat, and when the arm 

 hangs by the side, the head of the humerus, 

 distinct and prominent, is removed so much 

 from the under surface of the acromion, as it 

 were by the weight of the limb, that the 

 thumb can be easily placed between them. 

 When we take hold of the elbow and raise 



the arm vertically, the joint assumes more of 

 a natural form. Still, independent of its com- 

 parative diminution of size, it wants the ro- 

 tundity and fulness of contour ordinarily de- 

 rived from a proper development of muscular 

 covering. The elbow joint is perfect as to 

 its form and functions. This patient has 

 been under the writer's observation for many 

 years, and these symptoms have not varied. 



Anatomical characters of congenital ma/form- 

 ation of the shoulder joint with displace- 

 ment of the head of the humerus inwards. 

 We may consider the following as a good 

 example, showing the anatomical characters of 

 the congenital malformation of the shoulder 

 joint, with displacement inwards of the head 

 of the humerus ; the congenital defect ex- 

 isted in both shoulder joints. 



Case. " A female, astat 28, who had been for 

 many years a patient in the lunatic department 

 of the House of Industry, died of chronic in- 



