THE SHOULDER REGION 19 



cartilage, because the epiphyseal cartilages of the secondary 

 centres for the glenoid cavity only exist near its margin (p. 13). 



If the disease begins in the proximal end of the diaphysis of 

 the humerus and spreads either forwards, backwards, or laterally, 

 it will in time perforate the periosteum and infect the overlying 

 soft parts. Should it spread medially, it will perforate the 

 periosteum covering the intra-capsular part of the diaphysis 

 (Fig. 6). The infection will then be intra-capsular but extra- 

 synovial. The synovial membrane rapidly becomes involved 

 and the joint infected. If the disease spreads upwards, it must 

 involve the epiphyseal cartilage and epiphysis before it can 

 break through the articular cartilage into the joint. Lastly, 

 it may travel distally and infect the medullary cavity. 



Surgical Approach to the Shoulder- Joint. In Empycema 

 of the joint, good access is obtained by a vertical incision, 

 made midway between the coracoid process and the acromion. 

 The anterior fibres of the deltoid are divided and the dis- 

 tended capsule, which is then exposed, can be incised. A 

 pair of dressing forceps may be passed through the joint and 

 made to project posteriorly below the tendon of the teres 

 minor. The instrument may then be cut down upon from 

 behind and a drainage tube drawn through. 



In Tuberculous Disease, the joint may be approached either 

 from the anterior or from the posterior aspect. The latter 

 route, though more difficult, gives the better access (Kocher). 

 In the anterior method the approach is direct, and little damage 

 is done either to the deltoid or to its nerve of supply. By 

 rotating the humerus first medially and then laterally, it is 

 possible to elevate the muscles from the greater and lesser 

 tubercles, either sub-periosteally or sub-cortically, depending 

 on the age of the patient. The head of the humerus may be 

 removed through a comparatively small incision, but if the 

 glenoid cavity and neck of the scapula require to be excised, 

 some difficulty will be found in removing them by the anterior 

 method of approach. 



The posterior method of approach affords a much more 

 extensive view of the articulation. This is obtained by freeing 

 the trapezius and the deltoid from the spine of the scapula, by 

 sawing through the spine obliquely into the great scapular 

 notch, and by rotating forwards the acromion and the deltoid. 

 The capsule is opened above, where, according to Kocher, the 

 subsequent weakness matters least. 



