596 THE ARTERIES. 



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 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 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 profundse, 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. 



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

 below the lower border of the Teres major, and passes backward to the interval 

 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, to the outer side of the 

 humerus just above the external condyle, where it divides into two terminal 

 branches. One of these pierces the external intermuscular septum, and descends 

 to the space between the Brachialis anticus and Supinator longus, where it anasto- 

 moses with the recurrent branch of the radial artery ; while the other, the posterior 

 articular, descends along the back of the external intermuscular septum to the 

 back part of the elbow-joint, where it anastomoses with the posterior interosseous 

 recurrent, and across the back of the humerus with the posterior ulnar recurrent, 

 the anastomotica magna, and inferior profunda (Fig. 366). The superior profunda 

 supplies the Triceps muscle and gives off a nutrient artery to the upper end of the 

 humerus. Near its commencement it sends off a branch which passes upward 

 between the external and long heads of the Triceps muscle to anastomose with 

 the posterior circumflex artery, and, while in the groove, a small branch which 

 accompanies a branch of the musculo-spiral nerve through the substance of the 

 Triceps muscle and ends in the Anconeus below the outer condyle of the 

 humerus. 



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

 the middle of the arm. Passing downward 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 inner 

 condyle and olecranon, accompanied by the ulnar nerve, and terminates by anasto- 

 mosing with the posterior ulnar recurrent and anastomotica magna. It also 

 supplies a branch to the front of the internal condyle, which anastomoses with the 

 anterior ulnar recurrent. 



The anastomotica magna arises from the brachial about two inches above the 



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 Cases in Surgery. Porta also gives a 

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

 Patoligiche delle Arterie). 



