386 



BRACHIAL ARTERY. 



Fig. 271. 



In all cases of the high origin of one or other of the arteries of the fore-arm, the 

 extent in which the two vessels thus formed run separately must vary according to the 



height at which the main artery divides. The point 

 of division in the entire number of cases, without 

 reference to the particular branch given off, is 

 most frequently in the upper, less so in the lower, 

 and least so in the middle third of the arm. But 

 the early division of the main artery of the upper 

 limb may, as mentioned in connection with the 

 varieties of the axillary artery, take place within 

 the axilla, in which case it follows that the brachial 

 portion of the vessel is replaced, throughout its 

 whole extent, by two separate trunks. In 94 cases 

 out of 481 observed by R. Quain, or about one in five 

 and one-ninth, there were two arteries instead of one 

 in some part or in the whole of the arm. 



TJie position of the two arteries, in these cases, 

 is of much surgical interest. We shall here con- 

 sider only their position in the arm, and subse- 

 quently trace them in their irregular course in the 

 fore-arm. Usually they are close together, and 

 occupy the ordinary position of the brachial artery ; 

 but there are some peculiarities in their position 

 which require to be particularly noticed. 



The radial artery, when thus given off in the 

 arm, often arises from the inner side of the brachial, 

 then runs parallel with the larger vessel (the bra- 

 chial or ulnar interosseous), and crosses over it, 

 sometimes suddenly, opposite the bend of the 

 elbow, still covered by the fascia. It has been 

 found, but in a very few instances only, to perforate 

 the fascia, and run immediately under the skin, 

 near the bend of the elbow. 



Fig. 271. DISSECTION OP THE RIGHT ARM, SHOWING 

 AN EXAMPLE OF HIGH SEPARATION OP THE RADIAL 

 ARTERY FROM THE BRACHIAL, AND AN ENLARGED 

 MEDIAN ARTERY IN THE FORE- ARM (from Tiede- 

 mann). \ 



1, on the tendon of the latissimus dorsi, points to 

 the upper part of the brachial artery ; 2, the brachial 

 artery after giving off the radial ; 3, the radial rising 

 in the upper third of the arm and descending in its 

 usual situation in the fore-arm ; 3', its superficial 

 volar branch ; 4, the ulnar artery in its usual course, 

 forming at 5, the superficial palmar arch, from which 

 three of the palmar digital arteries and the princeps 

 pollicis take origin ; the radial supplying the branches 

 to the index finger and one side of the middle finger ; 



6, the superior profuuda branch of the brachial artery ; 



7, muscular branches ; 8, ulnar anastomotic ; 9, re- 

 current radial ; 10, anterior iuterosseous giving an 

 unusually large median branch which descends over 

 the wrist to unite with the superficial palmar arch. 



When the ulnar is the branch given off high 

 from the brachial, it often inclines from the posi- 

 tion of the brachial, at the lower part of the arm, 

 towards the inner condyle of the humerus. This 

 vessel generally lies beneath the fascia as it 

 descends, and superficially to the flexor muscles 



