392 



ULNAR ARTERY. 



place of origin was higher up the artery. See on this subject the description of the 

 peculiarities of the axillary and brachial arteries, pp. 381 and 385. 



Fig. 275. Fig- 275. ABNORMAL SUPERFICIAL ULNAR ARTERY 



RISING HIGHER THAN USUAL FROM THE BRAOHIAL. 



This figure has been taken from a pi-eparation in A. 

 Thomson's collection ; the drawing being planned after 

 that of a similar case represented by R. Quain. Tab. 

 xxxvi. Fig 1. 



a, biceps muscle covered by the deep brachial fascia ; 

 6, the same fascia in the fore-arm, which has been 

 opened in a considerable extent to show the radial artery 

 subjacent to it ; c, median nerve ; d, ulnar nerve ; 1, 

 on the biceps muscle, points to the brachial artery after 

 having given off an uluar artery higher up, and dividing 

 at 1', into the radial artery and a deep vessel correspond- 

 ing to the interosseous and a part of the usual ulnar ; 

 2, on the supinator longus muscle, points to the 

 radial artery ; 3, 3, artery which is given off by the 

 brachial in the arm, and which descending upon the fascia 

 takes the place of the ulna at the wrist ; 3', the same 

 continued into the superficial palmar arch, giving off 

 digital branches nearly in the usual manner, and joined 

 by a branch from the radial, 4, the superficial volar ; 

 5, digital branches ; towai'ds the thumb a commu- 

 nication of the superficial arch with the princeps pollicis 

 exists. 



Course. The position of the ulnar artery in the 

 fore-arm is more frequently altered than that of the 

 radial. When it arises in the usual way, the course 

 of this artery is not often changed ; but it has been 

 seen to descend apart from the tendon of the flexor 

 carpi ulnaris, instead of being close to its radial 

 border. 



In cases of high origin, it almost invariably descends 

 over the muscles arising from the inner condyle of the 

 humerus, only one exception to this rule having been 

 met with. CR. Quain, plate 36, fig. 2.) 



Most commonly it is covered by the fascia of the 

 fore-arm ; but cases also occur in which the vessel rests 

 on the fascia, and either continues in that position or 

 becomes subaponeurotic lower down, while the vessel 

 thus disposed is distributed after the manner of the 

 normal ulnar artery. The vessel from which the high 

 ulnar separates is afterwards divided into the radial 

 artery and the interosseous, the last of which is usually 

 derived from the ulnar ; it appears therefore probable 

 that the abnormal arrangement results from early 

 obstruction of the ulnar artery below the origin of the 

 interosseous, and the development of a superficial 

 vas aberrans, which unites the portion of vessel below 

 the obstruction with the axillary or brachial trunk. The 

 interosseous artery in such cases of abnormality thus 

 comprises not only the ordinary interosseous branch, 

 but likewise the portion of ulnar artery above the 

 obstruction ; and, in accordance with this view, we 

 find that the recurrent branches are derived from it. 



As to size, the ulnar artery presents some peculiarities which, being accompanied 

 by deviations of an opposite and compensating character in the radial artery, will be 

 noticed with that vessel. 



