THE ARTERIES 31 



from the upper part of the arch and entering the 

 dorsal wall of the oesophagus. 



3. The occipito-vertebral artery is a short branch arising 



from the dorsal part of the arch : it runs upwards 



immediately in front of the transverse process of the 



second vertebra, and divides into two : 



i. The occipital artery : which runs forwards, supply- 

 ing the side of the head and jaws. 

 ii. The vertebral artery : a large artery which runs 

 back alongside of and above the vertebral column, 

 and gives branches to the muscles of the body- 

 wall and to the spinal cord. 



4. The subclavian artery : arises from the arch immedi- 



ately behind the occipito-vertebral artery, and runs 

 outwards, supplying the shoulder and fore-limb. 

 Branches given off after the union of the two arches to 

 form the dorsal aorta. 



1. The coeliaco-mesenteric artery is a large median artery 



arising immediately beyond the point of union of the 

 two arches, or sometimes from the left arch just 

 before the union, and supplying the stomach and 

 intestines. Its branches are as follows : 

 L The coeliac artery : which divides into 



a. The gastric artery, supplying the stomach. 

 ft. The hepatic artery, supplying the liver and 



gall-bladder. 

 ii. The mesenteric artery : which divides into 



a. The anterior mesenteric artery, supplying the 



proximal part of the intestine. 

 ft. The posterior mesenteric artery, supplying 



the distal part of the intestine, 

 y. The splenic artery, supplying the spleen. 



2. The urinogenital arteries are four to six small arteries 



which arise from the ventral surface of the aorta 

 between the kidneys, and immediately divide into 

 right and left branches, supplying the kidneys, the 

 reproductive organs and ducts, and the fat bodies. 



3. The lujnbar arteries are small paired lateral branches 

 ^supplying the body-walls. 



