500 



THE MUSCLES AND FASCIAE. 



FIG. 319. Fracture of the middle of the 

 clavicle. 



In fracture of the acromial end of the clavicle, between the conoid and trapezoid ligaments, 

 only slight displacement occurs, as these ligaments, from their oblique insertion, serve to hold 



both portions of the bone in apposition. Fracture, also, 

 of the sternal end, internal to the costo-clavicular liga- 

 ment, is attended with only slight displacement, this 

 ligament serving to retain the fragments in close appo- 

 sition. 



Fracture of the acromion process usually arises from 

 violence applied to the upper and outer part of the 

 shoulder ; it is generally known by the rotundity of the 

 shoulder being lost, from the Deltoid drawing the frac- 

 tured portion downward and forward ; and the displace- 

 ment may easily be discovered by tracing the margin of 

 the clavicle outward, when the fragment will be found 

 resting on the front and upper part of the head of the 

 humerus. In order to relax the anterior and outer 

 fibres of the Deltoid (the opposing muscle), the arm 

 should be drawn forward across the chest and the elbow 

 well raised, so that the head of the bone may press the 

 acromion process upward and retain it in its position. 



Fracture of the coracoid process is an extremely rare 

 accident, and is usually caused by a sharp blow on the 

 point of the shoulder. Displacement is here produced 

 by the combined actions of the Pectoralis minor, short 

 head of the Biceps, and Coraco-brachialis, the former 

 muscle drawing the fragment inward, and the latter 

 directly downward, the amount of displacement being 

 limited by the connection of this process to the acromion 

 by means of the coraco-acromial ligament. In order to 

 relax these muscles and replace the fragments in close 

 apposition, the forearm should be flexed so as to relax 

 the Biceps, and the arm drawn forward and inward across the chest, so as to relax the Coraco- 

 brachialis ; the humerus should then be pushed upward against the coraco-acromial ligament, 

 and the arm retained in that position. 



Fracture of the surgical neck of the humerus (Fig. 320) is very common, is attended with 

 considerable displacement, and its appearances correspond somewhat with those of dislocation 

 of the head of the humerus into the axilla. The upper fragment is slightly elevated under the 

 coraco-acromial ligament by the muscles attached to the greater and lesser tuberosities ; the 

 lower fragment is drawn inward by the Pectoralis major, Latissimus dorsi, and Teres major ; and 

 the humerus is thrown obliquely outward from the side by the Deltoid, and occasionally elevated 

 so as to project beneath and in front of the coracoid process. The deformity is reduced by 



fixing the shoulder and drawing the arm outward and down- 

 ward. To counteract the opposing muscles, and to keep the 

 fragments in position, the arm should be drawn from the side 

 and pasteboard splints applied on its four sides ; a large conical- 

 shaped pad should be placed in the axilla, with the base turned 

 upward and the elbow approximated to the side, and retained 

 there by a broad roller passed round the chest ; the forearm 

 should then be flexed, and the hand supported in a sling, care 

 being taken not to raise the elbow, otherwise the lower frag- 

 ment may be displaced upward. 



In fracture of the shaft of the humerus below the inser- 

 tion of the Pectoralis major, Latissimus dorsi, and Teres major, 

 and above the insertion of the Deltoid, there is also consider- 

 able deformity, the upper fragment being drawn inward by the 

 first-mentioned muscles, and the lower fragment upward and 

 outward by the Deltoid, producing shortening of the limb and 

 a considerable prominence at the seat of fracture, from the 

 fractured ends of the bone riding over one another, especially 

 if the fracture takes place in an oblique direction. The frag- 

 ments may be brought into apposition b} 7 extension from the 

 elbow, and retained in that position by adopting the same 

 means as in the preceding injury. 



In fractures of the shaft of the humerus immediately below 

 the insertion of the Deltoid, the amount of deformity depends greatly upon the direction of the 

 fracture. If it occurs in a transverse direction, only slight displacement takes place, the upper 

 fragment being drawn a little forward ; but in oblique fracture the conibined actions of the 

 Biceps and Brachialis anticus muscles in front and the Triceps behind draw upward the 

 lower fragment, causing it to glide over the upper fragment, either backward or forward, 

 according to the direction of the fracture. Simple extension reduces the deformity, and 

 the application of splints on the four sides of the arm will retain the fragments in apposition. 



FIG. 320. Fracture of the surgical 

 neck of the humerus. 



