122 DISTRIBUTION OF THE ARTERIES. 



The posterior tibial artery, the smaller of the two, passes 

 along the posterior deep region of the thigh, to the hock, where 

 it ends in bifurcation. Its branches are, one that, runs into the 

 flexor pedis ; another to the upper and back part of the tibia ; 

 and small twigs to both the flexors. There are several ter- 

 minating branches, some ramifying subcutaneously, others 

 continuing down the leg internally over the tendon of the 

 flexor pedis, and ending at the lower part of the cannon in 

 divers small ramifications. 



The anterior tibial artery, after leaving the trunk, passes 

 down the fore part of the thigh, to the hock and metatarsal 

 bone, where it becomes the metatarsal artery. 



The metatarsal artery pursues its course downwards to 

 about two thirds the length of the leg ; it then gains the pos- 

 terior part of the latter ; a little above the fetlock, it divides 

 into three vessels : one forms an arc, (as in the fore extremity,) 

 from which come off the recurrents, and they anastomoze with 

 the posterior tibial artery ; the lateral divisions become the 

 plantar arteries. 



DISTRIBUTION OF VEINS IN THE HORSE. 



The two main venous trunks, the venai cava, anterior and 

 posterior, correspond to the anterior and posterior aortae. 



THE ANTERIOR VENA CAVA 



Forms the main trunk of the veins, returning the blood 

 from the head, neck, chest, and fore extremities. It is prin- 

 cipally formed by the concurrent union of the jugular and 

 axillary veins, and is situated at its formation in the space be- 

 tween the two first ribs, about midway between the sternum 

 and vertebras ; it also receives the pectoral, vertebral, dorso- 

 cervical, and inferior cervical veins, and the vena azygos. 



THE JUGULAR VEIN. 



It passes behind the condyle of the lower jaw, under the 

 parotid gland, and joins the external carotid artery, and 



