212 CIRCULATORY SYSTEM. 



ceivcs some small veins, principally thyroideal: during its course 

 it also receives many smalF branches — cutaneous, muscular, and 

 tracheal veins. Near its termination it receives a considerable 

 branch, the superjicial brachial vein, which originates in front of 

 the radius, about two-thirds of the length of the bone upward, 

 from the main brachial vein, ascends along the anterior border of 

 the biceps, and continues upward in the hollow between the 

 breast and arm, winding as it proceeds a little outward, to reach 

 the jugular : this by farriers is called the plat-vein — it is the one 

 we are in the practice of opening for lameness in the shoulder. It 

 receives some unimportant muscular and cutaneous branches in 

 the course of its ascent. 



27ie Vertebral Vein 



Is the fellow vessel to the vertebral artery : the two pursuing 

 their course together, on either side of the neck, from the head to 

 the chest, passing through the foramina in the transverse pro- 

 cesses of all the cervical vertebrae with the exception of the last. 

 This vein has communications with the occipital sinus and pos- 

 terior cerebral veins; but it owes its formation principally to the 

 veins coming from the medulla oblongata, and the spinal marrow 

 and its membranes : it also receives vessels from the deep-seated 

 muscles in the vicinity. In its course it runs above the artery, 

 and at the entrance of' the chest quits its companion to terminate 

 in the anterior vena cava, just behind the first rib. 



The Axillary Vein 



Forms the main channel for the return of the blood distri- 

 buted by the divisions and ramifications of the axillary artery (to 

 which it corresponds) to the various parts of the fore extremity. 

 Its forming branches may be arranged into sets — a superficial and 

 a deep-seated set: the former run for the most part immediately 

 underneath the skin ; the latter, exceeding them both in numbei 

 and size, accompany the arteries, among the muscles. Besides, 

 there exist divers vessels of communication between the two sets. 

 It will facilitate the description of these vessels, at the same time 

 that it is the most natural mode of proceeding, for us to descend 

 at once to the foot, and trace them from their origin : this will 

 direct our commencement from the 



Plantar veins. There is not, perhaps, a piece of vascular 

 structure in any part of any animal that can be exhibited as a 

 specimen of greater beauty of venous arrangement than the foot 

 of the horse : the sole displays a curious and intricate network of 

 small veins, and the laminai in every part shew a similar reticular 

 venous ramification, altogether giving the foot quite a covering of 



