486 ARTERIES. 



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 hemorrhage 

 ceases only when both vessels are compressed, botli 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 

 towards 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 anamolies 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 inwards and the muscle outwards, 

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

 inferior profunda may be mistaken for the main trunk, especially if enlarged, from the collateral 

 circulation having become established ; this may be avoided by directing the incision externally 

 towards the Biceps rather than inwards or backwards towards the Triceps. 



The lower part of the brachial artery is of extreme 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 tlie 

 brachial artery, from which it is separated by thebicipital fascia, and that in no case should this 

 vessel be selected for venesection, except in a part which is not in contact with 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 sub- 

 scapular 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 pre- 

 viously, in one " a long portion of the artery had been obliterated, and sets of vessels are descend- 

 ing 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 artery. Anastomotica magna. 



Muscular. 



The superior profunda arises from the inner and back part of the brachial 

 opposite the lower border of the Teres Major, and passes backwards to the in- 

 terval between the outer and inner heads of the Triceps muscle, accompanied 

 by the musculo-spiral nerve; it winds round the back part of the shaft of the 

 humerus in the spiral groove, between the Triceps and the bone, and descends 

 on the outer side of the arm to the space between the Brachialis Anticus and 

 Supinator Longus, as far as the elbow, where it anastomoses with the recurrent 

 branch of the radial artery. It supplies the Deltoid, Coraco-brachialis, and t 

 Triceps muscles, and whilst in the groove between the Triceps and the bone, it 

 gives off the posterior articular artery, which descends perpendicularly between 

 the Triceps and the bone, to the back part of the elbow-joint, where it anasto- 

 moses with the interosseous recurrent branch, and, on the inner side of the arm, 

 with the posterior ulnar recurrent, and with the anastomotica magna or inferior 

 profunda (Fig. 288). 



The nutrient artery of the shaft of the humerus arises from the brachial, about 

 the middle of the arm. Passing downwards, it enters the nutrient canal of 

 that bone, near the insertion of the Coraco-brachialis muscle. 



The inferior profunda, of small size, arises from the brachial, a little below 

 the middle of the arm; piercing the internal intermuscular septum, it descends 

 on the surface of the inner head of the Triceps muscle, to the space between the 



1 Chclius's Siirycry, vol. ii. pp. 254. See also White's engraving referred to by Mr. South, of 

 Hit- MMtftoaMwfatf bnim-hcs after ligature of the brachial, in White's Cases in Surge n/. Porta 

 also gives a case (with drawings) of the circulation after ligature of both brachial and radial. 

 Alterazioni Patoloyiche delle Arterie. 



aial. 



