ABDOMIXAL BLOOD VESSELS. 355 



responds, however, with, its human homologue. It arises from the 

 radial at about the junction of the proximal and middle thirds of 

 the antebrachium, and is covered at its origin by the M. pronator 

 teres (§ 701). It passes caudad and distad along the ental surface 

 of the flexor muscles, and joins the ulnar nerve at about the point 

 of its division into a dorsal and ventral branch. The artery divides 

 at this point, and the two branches accompany the two branches of 

 the ulnar nerve. 



ABDOMINAL BLOOD VESSELS. 



Posture. — Dorsicumbent, the Umbs fastened laterad with cords 

 (Pig. 76). 



§ 946. Preparation. — The arteries and veins should be injected 

 with plaster as directed above (§§ 352-362), or the thorax may be 

 opened and the thoracic aorta and postcava injected caudad ; the 

 latter is easier done if the thorax is to be studied on a different cat. 



§ 947. Exposure. — About half an hour after the injection is 

 finished, open the abdomen as directed for the exposure of the 

 viscera (§ 710). 



Vena Port.^. (See Table, § 915.) 



The study of the portal vessels will be greatly facilitated by injecting them. To do 

 this, turn the duodenum to the left, and extending along the mesoduodenum (§ 726), near 

 the edge of the duodenal part of the pancreas, will be seen a large vessel filled with blood 

 ( V. mesenterica superior). Inject this vessel toward the liver, inserting the canula about 

 opposite the caudal end of the pancreas. Employ uncolored plaster or that colored with 

 chrome green or yellow. All the larger portal vessels will be filled except the peripheral 

 part of the V. mesenterica superior, and that may be filled by reversing the direction of 

 the canula 



It will be necessary to change the position of the viscera often in 

 tracing the portal vessels. 



§ 948. V. mesenterica superior, az. (Fig. 103, 107, V. m. s.). — 

 This collects the blood from the small intestine. Trace it from the 

 point where it was injected, first peripherad along the small intes- 

 tine, and then centrad to a point opposite the pylorus. 



§ 949. V. mesenterica inferior, ae. (Fig. 107). — This usually empties into the pre- 

 ceding about opposite the ampulla of Vater (Fig. 84), or it may empty into the following, 

 as in man. It comes from the large intestine. 



§ 950. V. gastro-splenica, az. — This joins the portal slightly nearer the liver than tho 

 preceding (§ 950). — It comes from the spleen, from part of the stomach and from the gastro- 



