PECULIARITIES OF THE BEACHIAL AETERY. 



387 



It is occasionally placed between the integuments and the fascia ; and in a single 

 instance was found beneath the muscles. In one instance occurring in the dissect- 

 ing-room of the Glasgow University, the ulnar artery, given off from the humeral 

 at the middle of the arm, was observed to descend superficially behind the inner 

 condyle. 



The interosseous, after arising from the axillary or brachial artery, is commonly 

 situated behind the main artery, and, on reaching the bend of the elbow, passes 

 deeply between the muscles, to assume its usual position in the fore-arm. 



Lastly, when the radial has arisen high in the arm, the residuary portion of the 

 brachial (ulnar interosseous) has occasionally been observed descending, accompanied 

 by the median nerve, along the intermuscular septum towards the inner condyle of 

 the huinerus, as far as the origin of the pronator teres (which in the cases recorded 

 was found broader than usual), whence it turned outwards under cover of the muscle, 

 to gain the usual position at the^iniddle of the bend of the elbow. 



Fig. 272. ABERRANT ARTERY, SEPARATING FROM THE Fig. 272. 



BRACHIAL AT THE MIDDLE OF THE ARM, PASSING WITH 

 THE MEDIAN NERVE THROUGH THE INTERNAL INTER- 

 MUSCULAR SEPTUM, AND JOINING FARTHER DOWN 

 THE REGULAR ULNAR (from R. Quain). 



a, biceps muscle ; b, triceps ; c, c, divided pronator 

 teres ; d, d, d', median nerve, diverted from its usual 

 course, and passing with the aberrant artery through 

 the internal intermuscular septum ; e, e, e, ulnar 

 nerve in its usual course; 1, brachial artery, giving 

 off an aberrant artery at the middle of the arm ; 

 2, the usual radial artery ; 3, aberrant artery, with 

 the median nerve twining round it, passing at 3' 

 through the internal intermuscular septum ; 3", the 

 same farther down, and communicating at 4' with the 

 first part of the normal ulnar artery, 4, given off 

 from the brachial. 



The two arteries taking the place of the brachial 

 are in some instances connected near the bend of 

 the arm by an intervening trunk, which proceeds 

 from the larger (or ulnar interosseous) artery to the 

 radial or the radial recurrent, and varies somewhat 

 in its size, form, and course. More rarely the two 

 unusual arteries are actually re-united. 



The aberrant arteries, " vas aberrantia," alluded 

 to in the preceding statement, are long slender ves- 

 sels, which arise either from the brachial or the 

 axillary artery, and end by joining one of the 

 arteries of the fore-arm, or one of their branches. 

 In eight cases out of nine, observed by Quain, this 

 unusual vessel joined the radial; in the remaining 

 case it joined the radial recurrent, which arose 

 irregularly from the ulnar artery. Monro and 

 Meek el have each seen one case in which the 

 aberrant vessel joined the ulnar. This peculiarity 

 may be regarded, perhaps, as an approach to that 

 condition in which there is division of the brachial 

 artery and subsequent connection of its two parts 

 by an intervening branch. 



State of the arteries in both limbs. Inmost cases of the high division of the brachial 

 arteries the condition of the vessels is not the same in the right and left arms. In 

 61 bodies in which the high division existed, it occurred only on one side in 43 ; on 

 both sides, in different positions, in 13 ; and on both sides, in the same position, in 

 the remaining 5. 



Branches. It has been already mentioned (p. 381) that the superior profunda 



