536 THE BLOOD-VASCULAR SYSTEM. 



The application of a ligature to the brachial artery may be required in case of wound of 

 the vessel and in some cases of wound of the palmar arch. It is also sometimes necessary in, 

 cases of aneurism of the brachial, the radial, ulnar, or interosseous arteries. The artery may 

 be 'secured in any part of its course. The chief guides in determining its position are the sur- 

 face markings produced by the inner margin of the Coraco-brachialis and Biceps, the known 

 course of the vessel, and its pulsation, which should be carefully felt for before any operation is 

 performed, as the vessel occasionally deviates from its usual position in the arm. In whatever 

 situation the operation is performed, great care is necessary, on account of the extreme thinness 

 of the parts covering the artery and the intimate connection which the vessel has throughout its 

 whole course with important nerves and veins. Sometimes a thin layer of muscular fibre is 

 met with concealing the artery ; if such is the case, it must be cut across in order to expose the 

 vessel. 



In the upper third of the arm the artery may be exposed in the following manner : The 

 patient being placed supine upon a table, the affected limb should be raised from the side and 

 the hand supinated. An incision about two inches in length should be made on the inner 

 side of the Coraco-brachialis muscle, and the subjacent fascia cautiously divided, so as to avoid 

 wounding the internal cutaneous nerve or basilic vein, which sometimes runs on the surface of 

 the artery as high as the axilla. The fascia having been divided, it should be remembered that 

 the ulnar and internal cutaneous nerves lie on the inner side of the artery, the median on the 

 outer side, the latter nerve being occasionally superficial to the artery in this situation, and that 

 the venae comites are also in relation with the vessel, one on either side. These being carefully 

 separated, the aneurism needle should be passed round the artery from the inner to the outer 

 side. 



If two arteries are present in the arm in consequence of a high division, they are usually 

 placed side by side : and if they are exposed in an operation, the surgeon should endeavor to 

 ascertain, by alternately pressing on each vessel, which of the two communicates with the wound 

 or aneurism, when a ligature may be applied accordingly ; or if pulsation or haemorrhage ceases 

 only when both vessels are compressed, both vessels may be tied, as it may be concluded that 

 the two communicate above the seat of disease or are reunited. 



It should also be remembered that two arteries may be present in the arm in a case of high 

 division, and that one of these may be found along the inner intermuscular septum, in a line 

 toward the inner condyle of the humerus, or in the usual position of the brachial, but deeply 

 placed beneath the common trunk : a knowledge of these facts will suggest the precautions 

 necessary in every case, and indicate the measures to be adopted when anomalies are met 

 with. 



In the middle of the arm the brachial artery may be exposed by making an incision along 

 the inner margin of the Biceps muscle. The forearm being bent so as to relax the muscle, it 

 should be drawn slightly aside, and, the fascia being carefully divided, the median nerve will be 

 exposed lying upon the artery (sometimes beneath) ; this being drawn inward and the muscle 

 outward, the artery should be separated from its accompanying veins and secured. In this 

 situation the inferior prof unda may be mistaken for the main trunk, especially if enlarged, from 

 the collateral circulation having become established ; this may be avoided by directing the incis- 

 ion externally toward the Biceps, rather than inward or backward toward the Triceps. 



The lower part of the brachial artery is of interest in a surgical point of view, on account 

 of the relation which it bears to the veins most commonly opened in venesection. Of these 

 vessels, the median basilic is the largest and most prominent, and, consequently, the one usually 

 selected for the operation. It should be remembered that this vein runs parallel with the 

 brachial artery, from which it is separated by the bicipital fascia, and that care should be taken 

 in opening the vein not to carry the incision too deeply, so as to endanger the artery. 



Collateral Circulation. After the application of a ligature to the brachial artery in the 

 upper third of the arm, the circulation is carried on by branches from the circumflex and 

 subscapular arteries, anastomosing with ascending branches from the superior profunda. If the 

 brachial is tied below the origin of the profunda arteries, the circulation is maintained by the 

 branches of the profundae, anastomosing with the recurrent radial, ulnar, and interosseous 

 arteries. In two cases described by Mr. South, 1 in which the brachial artery had been tied some 

 time previously, in one ''a long portion of the artery had been obliterated, and sets of vessels 

 are descending on either side from above the obliteration, to be received into others which ascend 

 in a similar manner from below it. In the other the obliteration is less extensive, and a single 

 curved artery about as big as a crow-quill passes from the upper to the lower open part of the 

 artery. ' ' 



The branches of the brachial artery are the 



Superior Profunda. Inferior Profunda. 



Nutrient. Anastomotica Magna. 



Muscular. 



1 Chelius's Surgery, vol. ii. p. 254. See also White's engraving, referred to by Mr. South, of the 

 anastomosing branches after ligature of the brachial, in White's Gases in Surgery. Porta also gives a 

 case (with drawings) of the circulation after ligature of both brachial and radial (Alteraziom 

 Patoligiche delle Arterie). 



