General inflammatory enlargement of the arm is rare ; it sometimes appears as a con comitant affection with inflammation of the veins of the arm consequent oil the operation of phlebotomy, in which case it not unfre quently happens that abscesses form along the course of the sheath of the brachial artery ; red streaks along the course of the lymphatics and enlargement of the lymphatic glands are sometimes present in consequence of disease or inflammation affecting the hand or fore-arm.
Amputation of the arm below the insertion of the deltoid may be performed either by the circular incision or the double flap ; when the latter method is practised, the flaps should be formed on the external and internal sides, by which the more important vessels and nerves will be included in the internal flap.
When circumstances require the performance of amputation above the insertion of the del toid, the circular operation should never be practised, for the following reason ;—in order to obtain a sufficiency of covering for the bone, the pectoralis major, latissimus dorsi, and teres major would all be detached from their inser tions, a consequence of which would be that the contractions of these muscles in opposite di rections, by drawing asunder the edges of the wound, would not only render complete appo sition difficult in the first instance, but more over their continued action would have the effect of converting the wound into an ulcer, which it would be extremely difficult if not impossible to heal ; therefore, whenever we have to amputate so high up, it is the more judicious mode of proceeding to make a flap including so much of the deltoid muscle as will form a sufficient covering for the stump.
The importance of attending to the foregoing circumstances was first pointed out by Louis, the learned secretary to the French Academy of Surgery.
The arteries which require to be tied after amputation of the arm below the insertion of the deltoid are the brachial and inferior pro funda on the internal side ; on the external side there are often two branches of the superior profunda requiring a ligature, one of which accompanies the musculo-spiral nerve, and the other runs in the substance of the triceps.
When it becomes necessary to tie the bra chial artery on account of a wound or aneu rism, the varieties of its relation to the median nerve should be carefully borne in mind ; at the upper part of the arm this artery has the median nerve external to it, and the ulnar nerve to its inner side ; in the middle of the arm the median nerve crosses the artery in general superficial to it, but sometimes under neath it, while in the lower part of the arm this nerve is invariably on its inner side.
When called upon to expose the brachial artery for the purpose of tying it, the surgeon should recollect that the course of the artery may be readily determined by a line drawn from the coracoid process to a point midway between the condyles of the humerus on the anterior surface of the elbow ; hence his in cision for the purpose of exposing the brachial artery should be always made along the course of this line and perpendicular to the axis of the os humeri. (See BRACHIAL ARTERY.)