96 IOWA ACADEMY OF SCIENCE Vol. XXVI, 1919 



VARIATIONS FROM THE NORMAL BRANCHING 



In discussing the variations from the normal, one branch will 

 be considered at a time and in the same order as presented above. 



The splenic artery presents peculiarities in the number and ar- 

 rangement of its branches mainly concerning the. short gastric 

 arteries. There may be one, two or more of these branches 

 coming off at the same place or at intervals from the splenic. 

 By far the most common arrangement is where but one or two 

 branches come off together as shown in all the figures. While 

 there are variations in the number and arrangement of the splenic 

 branches they need no further discussion. I would mention a pos- 

 sible variation, however, which I was unable to note in the rab- 

 bits studied, that is, the possibility of the splenic artery arising 

 directly from the abdominal aorta. In one case, the splenic, while 

 originating on the cceliac, came off at the base. Cases where the 

 origin of the splenic was on the aorta have been noted in this 

 laboratory while Piersol mentions the same condition as a pos- 

 sible variation in man. 



The left gastric artery and its branches present by far the most 

 interesting variations. From a condition which has been desig- 

 nated as the normal (figures 7:1, 2; 8:3), in which case the vessel 

 immediately divides into three main branches, the following vari- 

 ations have been noted and figured. In figure 8 :4 the dorsal branch, 

 which is always shown in the figures as a short unbranched vessel, 

 comes off the right branch instead of having its origin in common 

 with the right and left branches. This condition is shown in fig- 

 ure 8 :6 also. In figure 8 :5 and 7 its origin is on the left branch. In 

 figure 8:8 two vessels are shown, one from the right branch and 

 the other from the left. It is interesting to note how far removed 

 these origins may be from the normal as shown in figure 8 :5 and 8. 

 The right and left branches show considerable variation in their 

 origin. In figure 8:5 and 6 the origins on the cosliac are quite far 

 apart. The origin of the branch which anastomoses with the 

 right gastric artery also varies considerably as shown in figure 8:5, 

 6, 7 and 8. 



The hepatic artery, which in the normal condition is a continua- 

 tion of the coeliac, after giving off the left gastric artery, is shown 

 in figure 8:6 and 8, in what appears to be a continuation of the right 

 branch of the right gastric artery. The facts are, however, that the 

 hepatic artery, in this case, does not give off the gastroduodenal ar- 

 tery after the left gastric, but the hepatic and the gastroduodenal 

 arteries are given off before a part or all of the left gastric, while in 



