276 



APPLIED ANATOMY. 



it lies may be unusually deep and necessitate a special effort to divide it. On the face 

 of the stump the artery is to be looked for to the inner side of the bone in the upper 

 two-thirds of the arm and anteriorly in the lower third. Lying on it will be the 

 median nerve and to its inner side the ulnar nerve. At the level of the insertion of 

 the deltoid the radial (musculospiral) nerve, accompanied by the (superior) profunda 

 artery, will be posterior or toward the outer side. The superior ulnar collateral (in- 

 ferior profunda) artery is given off at the level of the insertion of the coracobrachialis 

 muscle, which is about opposite the insertion of the deltoid. It accompanies the ulnar 

 nerve. A nerve may be seen lying between the biceps and brachialis anticus. It is the 

 musculocutaneous which becomes superficial just above the bend of the elbow (Fig. 288) . 



Biceps 

 Musculocutaneous nerve 



Median nerve 



Brachial artery 

 Internal cutaneous nerve s 



Ulnar nerve and inferior 

 profunda artery 



Coraco-brachialis 



Musculospiral nerve and 

 superior profunda artery 



Brachialis anticus 



Deltoid 



Triceps 



Triceps 



FIG. 288. Amputation just above the middle of the arm. 



Five cm. (2 in. ) above the elbow the inferior ulnar collateral (anastomotica 

 magna) artery may be expected to be encountered passing down and in over the 

 brachialis anticus muscle. 



FRACTURES OF THE HUMERUS. 



Fractures of the Shaft of the Humerus. There seems to be but little doubt 

 that in many cases the character of displacement of the fragments in fracture of the 

 shaft of the humerus is due to the mode of injury and not to muscular action. This 

 being so accounts for there being less uniformity in these fractures than in those 

 higher up, which have already been considered. There are some cases, however, in 

 which muscular action does play a part and the possible influence of the muscles 

 should be understood. 



The line of fracture is usually more or less oblique, in rare cases nearly trans- 

 verse, but the displacement is often not marked. Notwithstanding this latter fact, 

 non-union of fracture of the shaft of the humerus is one of the most frequent of any 

 in the body. 



Muscular action shows its influence most markedly in producing displacements 

 in three directions, viz., in towards the body, out away from the body, and directly 

 anteriorly. 



