THE SHOULDER-GIRDLE. 



247 



Supraspinatus 

 Muscle 



To aid in the reduction McBurney devised a hook which he inserts into the upper 

 fragment, pulling it toward the glenoid cavity. 



EPIPHYSEAL SEPARATIONS. 



The epiphyses that are liable to separation are those of the coracoid process, 

 the acromion process, and the upper end of the humerus. 



Separation of the Coracoid Epiphysis. The coracoid process has three 

 separate centres of ossification which fuse with the body of the bone from the fifteenth 

 to the twentieth year. Therefore displacements occurring before the latter age may 

 be separations of the epiphysis and not true fractures, particularly if the line of sepa- 

 ration runs through the base of the coracoid. 



Separation of the Acromion Epiphysis. The acromion process is cartilag- 

 inous up to the fifteenth year. Then two centres appear and the epiphysis unites 

 with the rest of the spine of the scapula about the twentieth year or later. The epi- 

 physeal line runs posterior to the acromioclavicular joint, just behind the angle of the 

 spine of the scapula. It has been suggested that many cases diagnosed as sprains and 

 contusions of the shoulder are really epiphyseal separations of the acromion process. 



Separation of the Epiphysis of the Upper End of the Humerus. The 

 upper end of the humerus has three centres of ossifica- 

 tion, one for the head and one each for the greater and 

 lesser tuberosities. These three centres are blended by 

 the seventh year, and the whole epiphysis unites with the 

 shaft at about the age of twenty-five years. 



The epiphyseal line follows the lower half of the 

 anatomical neck and then passes outward to the insertion 

 of the teres minor muscle. This brings the outer end of 

 the epiphyseal line some distance away from the joint, 

 while the inner portion of the line is within the joint. 

 Disease of this region may therefore follow the epiphyseal 

 cartilage into the joint. A separation of the epiphysis 

 from injury will implicate the joint. 



The surgical neck of the humerus lies a short dis- 

 tance below the epiphyseal line and farther away on the 

 outer side than on the inner. The line of the epiphysis 

 rises higher in the centre of the bone than on the sur- 

 face, making a sort of cap for the end of the diaphysis. 

 The symptoms of epiphyseal separation are almost 

 exactly the same as those of fracture of the surgical neck 

 (see page 245). 



The supraspinatus is the main agent in tilting the 

 upper fragment outward, while the muscles inserted into 

 the bicipital ridges, the pectoralis major into the outer 

 ridge and the latissimus dorsi and teres major into the 

 inner, draw the lower fragment inward. The relative 

 position of the fragments when the lower is displaced outward is seen in Fig. 262. 



AMPUTATIONS AND RESECTIONS OF THE SHOULDER. 

 AMPUTATION AT THE SHOULDER-JOINT. 



The many different methods of amputating at the shoulder may for our purposes 

 be divided into two classes, the flap method and the racket method. 



The Flap Method. One large flap may be made to the outer side and a 

 short one to the inner side (Dupuytren) or they may be made anteroposteriorly 

 (Lisfranc). The flap operations were done with long knives by transfixion, as they 

 originated before the discovery of general anaesthesia and by them the member was 

 removed with great rapidity (Fig. 263). 



In Dupuytren 1 s method the arm was raised to a right angle with the body and the 

 deltoid muscle grasped with one hand while the knife was inserted beneath it, entering 



FIG. 262. Detachment of the 

 epiphysis of the upper end of the 

 humerus. 



