172 THE SURGICAL ANATOMY OF THE HORSE 



and articular branches to the elbow joint. As already stated, the nutrient 

 artery of the humerus is also commonly a collateral branch of this 

 vessel. 



(5) "The Af'tery to the Biceps Muscle. — This branch comes off anteriorly 

 from the brachial artery. It may arise immediately opposite, slightly 

 above, or a little below the origin of the ulnar branch. It passes forwards 

 and usually slightly downwards, and splits up into ascending and descend- 

 ing branches, which are expended in the muscle from which the artery 

 derives its name. 



Like the axillary, the brachial artery is in such a protected position 

 that it is afforded a considerable degree of immunity against injury. 

 It may, however, suffer severe injury in cases of fracture of the shaft of 

 the humerus, in which cases, as indicated in our chapter dealing with 

 Fractures, treatment is of little use. 



Not infrequently also the artery is injured in those severe wounds 

 which are caused by the shaft passing from the front between the limb 

 and chest wall just below the shoulder joint, in which cases, unless the 

 wound has a very extensive external opening, it is impossible adequately to 

 treat the damaged vessel. 



The ulnar branch is comparatively superficially placed, and is in 

 consequence exposed to greater risk of injury. Section of it is not a 

 matter of great moment, since a ligature may be readily applied to the 

 vessel by making a vertical incision in the middle of the forearm in the 

 groove between the flexor metacarpi externus and flexor metacarpi 

 medius muscles, provided the injury to the vessel is below this point, 

 as in accidental section whilst performing ulnar neurectomy when the 

 operator fails to secure the severed end of the vessel at the seat of 

 neurectomy. 



The Anterior Radial Artery. — Of the two terminal divisions of the 

 brachial artery, this vessel is much the smaller. From the point where 

 the brachial artery divides the anterior radial division passes obliquely 

 downwards, forwards, and outwards. It is long and slender, and takes 



