624 Proceedings oftJie Royal IrisJi Academy. 



LXXXY. — ilrxTipiE Eexal AEiEErES. By A. ]!JLi.CAi,isTEE, 3I.D., 

 P.R.S., Professor of Anatomy, University of Dublin. 



[Eead, June 26th, 1882.] 



IjREE&rLAEiTiES of the renal arteries are the commonest varieties met 

 Tvith among the abdominal vessels ; indeed these arteries present some 

 fonn of variation in three cases out of every seven. 



Leaving out of account those varieties ■which are associated "with 

 misplaced, or horseshoe kidneys, "we may classify the many forms of 

 anomalous renal arteries as follows : — 



1. Varieties of Numlers. — The arteries may be — (a) diminished in 

 number, and this under two conditions — («), with absence of the left 

 kidney, as in "Weissman's case;^ or (5), with the origin of both renals 

 from a common stem arising fi'om the front of the aorta, as in Portal's 

 well-known instance. Yery much more commonly (yS) the arteries are 

 increased in number. 



]l'trultiple renal arteries may be threefold — {a), Most commonly the 

 additional branches spring from the aorta ; (^), or they may come 

 from other soui'ces ; or (<?) there may be a co-existence of additional 

 vessels from both sources. 



Of the fii'st class, there have been described cases of, 



one, 



two, ( °, 1 j +v,"!^o f left aortic 



or 1 . , T .,, i ' ( renals 



three 



associated with 



Of these twelve varieties, I have not found the variety of two right 

 and four left, and I have seen, in addition, single instances of t]i:xe 

 right and five left, and three right and six left. The commonest form, 

 next to the normal condition of one on each side, is two on the right and 

 one on the left. The second commonest condition is the reverse ; but 

 among the forms with larger numbers the greatest number is more fire- 

 quently seen on the left than on the right side. In all these cases one 

 vessel arises in the position of the normal renal ; a second commonly 

 springs from the aorta much lower down, generally on the level of, or 

 below, the inferior mesenteric ; the third, when present, is a very short 

 distance above the normal renal, very close to the supra-renal, and on 

 the level of the superior mesenteric (this branch is not to be confounded 



^ In cases like those described by Hunter (Med. Trans, of tbe London Coll. of 

 Physicians, vol. iii. 1785, p. 250), and by John Eeid (Phys- Path, and Anat. 

 Eesearches, p. 417), where there were two kidneys on the right, and none on the 

 left, there were two right renal arteries, an upper and a lower, and none on the 

 left. For other cases, see Edin. Med. Journal, July, 1879. 



