ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 



sembles much the specimen alluded to by Mr. 

 Key. The newly formed socket reached from 



Fig. 438. 



Dislocation forwards and downwards. (Original, 

 from the museum of the College of Surgeons, Dublin.) 



the edge of the glenoid cavity, to about one- 

 third across the subscapular fossa; a deep cup 

 was formed for the reception of the dislocated 

 head of the hnmerus; the inner margin of 

 this cup was fully half an inch above the level 

 of the subscapular fossa; the glenoid cavity 

 had lost all cartilaginous investment ; it was 

 rough on its surface from bony deposition, 

 and its inner margin was elevated somewhat 

 into a sharp ridge, so as to form part of the 

 margin of the new articular cavity for the 

 head of the humerus. 



3. Dislocation backwards of the head of the 

 humerus on the dor sum of the scapula, the result 

 of accident. In this dislocation the arm is 



Fig. 439, 



Dislocation on the dorsum of the scapula. 



directed from above downwards, inwards, and 

 forwards. The deformity of the joint is well 

 seen by viewing it in front, where a deficiency 



611 



is noted of the normal roundness of the artieu- 

 lation. When we look at the shoulder side- 

 ways, the head of the humerus maybe seen to 

 form a remarkable saliency behind the posterior 

 angle of the acromion. In this dislocation the 

 head of the bone is thrown on the posterior 

 surface of the scapula immediately below the 

 spine of this bone, and there forms a very re- 

 markable protuberance, and when the elbow is 

 rotated as far as practicable this protuberance 

 moves also. The dislocated head of the bone 

 may be easily grasped between the fingers, and 

 distinctly felt resting below the spine of the 

 scapula ; the motions of the arm are impaired, 

 but not to the same extent as in the other 

 luxations of the shoulder, and the longitudinal 

 axis of the humerus may be observed to run 

 upwards, backwards, and to a point, evidently 

 behind the situation of the glenoid cavity. In 

 Guy's Hospital Reports* Sir A. Cooper has 

 published a case of this species of dislocation, 

 from which we abstract the following, 



Case. " Mr. Key has given me the par- 

 ticulars of the following case. Mr. Complin 

 was 52 years of age, and had been the sub- 

 ject of epileptic fits; one of them, which 

 was particularly severe, occurred one morning 

 while he was in bed, and in his violent con- 

 vulsive strugglings his shoulder became dis- 

 located on the dorsum of the scapula, present- 

 ing the ordinary symptoms of this accident in 

 which dislocation had never been reduced." 

 The circumstance most peculiar in this case 

 was, that the head of the bone could by ex- 

 tension be drawn into its natural situation in 

 the glenoid cavity ; but so soon as the force 

 ceased to be applied it slipped back again in 

 the dorsum of the scapula, and all the appear- 

 ances of dislocation were renewed. The se^ 

 cond peculiarity consisted in a sensation of 

 crepitus as the bone escaped from its socket, 

 so as to lead to a belief that the edge of the 

 glenoid cavity had been broken off. The 

 patient was unable to use or even to move the 

 arm to any extent, nor could he by his own 

 efforts elevate it from his side, and although 

 he lived seven years after the occurrence of 

 the epileptic fit, he never recovered the use of 

 the limb. Mr. Key sent the following note 

 of the dissection of the dislocated shoulder in 

 this case to Sir A. Cooper : - "The dislocation 

 of Mr. Complin's shoulder arose from muscu- 

 lar action alone in a paroxysm of epilepsy, 

 and during his life it was thought probable 

 that a portion of the glenoid cavity had been 

 broken off, or a piece of the head of the os 

 humeri, or perhaps the smaller tubercle, and 

 that either of these injuries would account for 

 the head of the bone not remaining in its na-' 

 tural cavity when reduced. But the inspec- 

 tion, post-mortem, proved that the cause of" 

 this symptom was the laceration of the tendon 

 of the suoscapularis muscle, which was found to 

 adhere to the edge of the glenoid cavity, and ' 

 was much thickened and altered in its cha- 

 racter from its laceration, and from its very 



* Astley Cooper on Dislocations, &c., page 384.,- 

 edition 1842, by Mr. B. Cooper. 



ft ft 8 



