270 
have become, like the visceral arteries, reduced in numbers, and the 
frequent occurrence of multiple renal arteries is to be regarded most 
probably as a reversion to the more primitive multiple metameric con- 
dition. J. Yutm Mackay (3) has pointed out that the uterine and 
vaginal arteries belong possibly to this group. | 
Surgically, multiple renal arteries are interesting as a possible © 
complication of the operation of nephrectomy. If the arteries all pass 
to the hilum of the kidney they will probably be all secured in ligating 
the pedicle. But if they pass to either the upper or the lower end of 
the kidney or to its dorsal surface there is the possibility of their 
being missed. Accessory renal arteries occur in 43 %, (1) of bodies 
examined; 6,9 °/, (2) have an accessory renal artery arising from the 
aorta above the level of the superior mesenteric and entering the 
anterior end of the kidney, 4 °/) (2) have an accessory renal artery 
arising from the aorta and passing to the lower end of the kidney; 
while 0.9 %, (2) have a similarly disposed artery arising from the common 
iliac arteries. Such situated arteries would be most lkely to escape 
ligature and give rise to hemorrhage, especially if, as in the first case 
described above, such arteries were as large in calibre as the radial 
of the arm. Treves, Tavtor, and Barker have called attention to the 
necessity of being on the look out for such aberrant supernumerary 
renal arteries. Perhaps the only certain way to avoid the possibility 
of accident would be to pass the loop of the ligature round the kidney. 
References. 
1) Macauister, Multiple Renal Arteries. Journ. Anat. and Physiol, 
Wolk 7. 
2) Report of Collective Investigation Committee, presented by ARTHUR 
THomson M.A., M.B. Journ. Anat. and Physiol., Vol. 25. 
3) Mackay, J. Yuur, in: Memoirs and Memoranda in Anatomy. 
4) .Kater Norman W., Journ. of Anat. and Physiol., Vol. 36, p. 77. 
5) Young and TxHomson, Multiple Renal Arteries. Journ. Anat. and 
Physiol., Oct. 1903. 
) Newman, Medical Press and Circular, May 1899. 
) SUTHERLAND and Epineron, Glasgow Medical Journal, February 1898, 
and Glasgow Hospital Reports, Vol. 3. 
