ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 



607 



bone upon some of the nerves of the brachial 

 plexus. 



Anatomical characters of the dislocation into 

 the axilla. Sir Astley Cooper informs us 

 that he dissected two recent cases of tin's dis- 

 location : "First case : A sailor fell from the 

 yard-arm on the ship's deck, injured his skull, 

 and dislocated the arm into the axilla. He 

 was brought into St. Thomas's Hospital in a 

 dying state, and expired immediately after. 

 On the next day the shoulder joint was mi- 

 nutely examined, and the following were the 

 appearances found : On removing the integu- 

 ments, a quantity of extravasated blood pre- 

 sented itself in the cellular membrane, lying 

 immediately under the skin, and in that which 

 covers the axillary plexus of nerves, as well 

 as in the interstices of the muscles, extending 

 as far as the cervix of the humerus, below 

 the insertion of the subscapularis muscle. 

 The axillary artery and plexus of nerves were 

 thrown out of their course by the dislocated 

 head of the bone, which was pushed back- 

 wards upon the subscapularis muscle. The 

 deltoid muscle was sunken, with the head of 

 the bone. The stipra-and infra-spinati were 

 stretched over the; glenoid cavity and inferior 

 costa of the scapula. The teres major and 

 minor had undergone but little change of po- 

 sition ; but the latter, near its insertion, was 

 surrounded by extravasated blood. The 

 coraco-brachialis was uninjured. In a space 

 between the axillary plexus and coraco-bra- 

 chialis, the dislocated head of the bone, co- 

 vered by its smooth articular cartilage and by 

 a thin layer of cellular membrane, appeared. 

 The capsular ligament was torn on the whole 

 length of the inner side of the glenoid cavity, 

 and would have admitted a much larger body 

 than the head of the os humeri through the 

 opening. The tendon of the subscapularis 

 muscle which covers the ligament, was also 

 extensively torn. The opening of the liga- 

 ment, through which the tendon of the long 

 head of the biceps passed, was rendered larger 

 by laceration, but the tendon itself was not 

 torn. The head of the os humeri was thrown 

 on the inferior costa of the scapula, between 

 it and the ribs, and the axis of its new situ- 

 ation was about an inch and a half below the 

 centre of the glenoid cavity from which it 

 had been thrown. The second case" adds Sir 

 Astley Cooper, " which I had an opportunity 

 of examining, was one in which the disloca- 

 tion had existed five weeks, and in which very 

 violent attempts had been made to reduce the 

 dislocated bone, but without success. The sub- 

 ject of the accident was a woman, fifty years 

 of age. All the appearances were distinctly 

 marked ; the deltoid muscle being flattened, 

 and the acromion pointed ; the head of the 

 bone could also be distinctly felt in the axilla. 

 The skin had been abraded during the at- 

 tempts at reduction, and the woman apparently 

 died from the violence used in the extension. 

 Upon exposing the muscles, the pectoralis 

 major was found to have been slightly lacer- 

 ated, and blood was effused amongst its fibres; 

 the latissimus dorsi and teres major were not 



injured ; the supra-spinatus was lacerated in 

 several places ; the infra-spinatus and teres 

 minor were torn, but not to the same extent 

 as the former muscle ; some of the fibres of 

 the deltoid muscle, and a few of those of the 

 coraco-brachialis, had been torn, hut none of 

 the muscles had suffered so much injury as 

 the swpra-spinatus. The biceps was not in- 

 jured. Having ascertained the injury which 

 the muscles had sustained in the extension, 

 and, in some degree, the resistance which they 

 opposed to it, I proceeded to examine the 

 joint. The capsular ligament had given way 

 in the axilla, between the teres minor and sub- 

 scapularis muscles ; the tendon of the sub- 

 scapularis was torn through at its insertion 

 into the lesser tubercle of the os humeri, and 

 the head of the bone rested upon the axillary 

 plexus of nerves and the artery. Having de- 

 termined these points by dissection, I next," 

 says Sir Astley Cooper, " endeavoured to re- 

 duce the bone, but rinding the resistance too 

 great to be overcome by my own efforts, I 

 became very anxious to ascertain its origin. 

 I therefore divided one muscle after another, 

 cutting through the coraco-brachialis, teres 

 major and minor, and infra-spinatus muscles. 

 Yet still the opposition to my efforts re- 

 mained, and with but little apparent change. 

 I then conceived that the deltoid must be the 

 chief cause of my failure, and, by elevating 

 the arm, I relaxed this muscle ; but still could 

 not reduce the dislocation. I next divided 

 the deltoid muscle, and then found the supra- 

 spinatus muscle my great opponent, until 1 

 drew the arm directly upwards, when the 

 head of the bone glided into the glenoid 

 cavity. The deltoid and supra-spinatus muscles 

 are those which most powerfully resist reduc- 

 tion in this accident." This dissection ex- 

 plains the reason why the arm is sometimes 

 easily reduced, soon after the dislocation, by 

 raising it suddenly above the horizontal line, 

 and placing the fingers under the head of the 

 bone, so as to lift it towards the glenoid cavity, 

 which will sometimes prove effectual, because, 

 in this position, the muscles are relaxed, so as 

 no longer to offer any resistance to reduction. 

 Sir Philip Crampton has adduced an example 

 of dislocation of the shoulder joint, which 

 illustrates in a satisfactory manner the anatomy 

 of a recent case of dislocation into the axilla. 

 Case. " In the year 1808, a labouring man 

 was brought into the County of Dublin In- 

 firmary in a dying state : the persons who 

 carried him stated that he had been engaged 

 in digging under the foundation of a house 

 that had been burned ; that a part of a par- 

 tition wall fell upon him, and that they had 

 found him buried under the rubbish : the man 

 did not survive more than two hours. On 

 examining the body eighteen hours after death, 

 it was observed, that in addition to the injury 

 of the head, which had proved fatal, the right 

 hunKTiis was dislocated into the axilla. To 

 this part I directed the whole of my attention. 

 I made a careful dissection of the joint, pre- 

 viously to reducing the dislocation, and was 

 so fortunate as to obtain a drawing of the 



