THE ARM. 275 



arm, it then leaves the artery. Below the middle, if the search is made too far 

 posteriorly, the ulnar nerve and basilic vein will be encountered. The ulnar nerve 

 should not be seen, the basilic vein and median nerve and above the middle of the 

 arm the medial antebrachial (internal) cutaneous nerve are to be displaced to the 

 inner side. 



The needle is to be passed from within outward. Care must be taken not to 

 mistake a large superior or inferior profunda for the main trunk. A high division 

 of the brachial may give two vessels of approximately equal size. Of course, in such 

 a case both must be ligated. 



Collateral Circulation. If the ligature is placed, above the profunda (superior) 

 branch, the anterior and posterior circumflex will anastomose with the profunda 

 (superior) and superior ulnar collateral (inferior profunda) below. If the ligature is 

 placed between the profunda and superior ulnar collateral arteries, the profunda 

 (superior) will anastomose below with the radial recurrent and posterior interosseous 

 recurrent on the outer side and will also communicate with the inferior ulnar 

 collateral (anastomotica magna) and superior ulnar collateral (inferior profunda) 

 on the inside (Fig. 287). If below the superior ulnar collateral (inferior profunda) 

 then the profunda (superior) would anastomose with the radial and posterior inter- 

 osseous recurrents on the outside, and the superior ulnar collateral (inferior profunda) 

 with the inferior ulnar collateral (anastomotica magna) and the anterior and posterior 

 ulnar recurrents. 



AMPUTATION OF THE ARM. 



In amputation one has to deal with a part of the body that is approximately 

 cylindrical in shape and that contains only a single bone entirely surrounded by 

 soft parts. The circular method is more applicable to amputation of the arm below 

 the insertion of the deltoid than to any other part of the body, but nevertheless in 

 some cases, particularly in muscular arms, difficulty may be experienced in turning 

 back the cuff. In such cases the cuff is slit by the surgeon and the operation 

 becomes one of square skin flaps. For this reason flap amputations are usually to 

 be preferred. 



The arm may be amputated at any place, high up or low down. Artificial 

 appliances for the upper extremity are comparatively useless; hence the height of 

 division of the bone is determined by the injury. 



As it is desirable to retain the head of the bone and tuberosities, if pos- 

 sible, in order to preserve the shape of the shoulder and retain the attachment 

 of the muscles, amputation may be done through the surgical neck. This is just 

 below the epiphyseal line. In performing a flap amputation the soft parts should 

 cover or cap the bone like a hemisphere : therefore the total length of the flaps should 

 be equal to one-half the circumference of a sphere whose diameter is the diameter of 

 the limb at the point of section of the bone. If the diameter of the limb is 4 inches, 

 then the total length of the flaps should be approximately 6 inches. If the flaps 

 were of equal length then each would be 3 inches long. If there was only one flap, 

 it would be 6 inches long. 



It is an axiom in surgery that in flap amputations the artery should be contained 

 in the shorter flap. The operator should accurately know the course of the artery 

 and avoid making his flaps in such a manner as to bring the vessel in the angle of the 

 wound. Otherwise the artery is liable to be split. In a high amputation the 

 external flap may be long and the internal short. In the middle of the arm antero- 

 posterior flaps are preferred and the artery is included in the posterior flap. If the 

 amputation is in the lower third and the flaps are anteroposterior, then the artery of 

 necessity is in the anterior flap. 



Above the middle of the arm the deltoid, coracobrachialis, and biceps muscles 

 are free and therefore retract markedly when cut. In the middle the biceps only is 

 free and the same is the case in the lower third. The triceps and brachialis anticus 

 are attached to the bone and therefore retract but little when cut. Surgeons have 

 called attention to the necessity of being careful to see that the radial (musculospiral) 

 nerve is properly divided, otherwise it may be torn by the saw. The groove in which 



