466 THE ARTERIES OF THE ABDOMEN. 



arising 1 above the normal trunk being more frequent than one arising below : the super- 

 numerary vessel would appear to be more frequent on the left side than on the right. Three 

 arteries on one side occur in about 3 per cent. ; and in rarer cases four, five, or even six 

 separate vessels have been seen. An intermediate condition is that in which the trunk 

 divides into branches immediately after its origin from the aorta. An accessory renal artery 

 may proceed from the inferior phrenic, the spermatic, a lumbar artery, or the inferior 

 mesenteric, from the bifurcation of the aorta, or the middle sacral artery, from the common 

 iliac (in about 1 per cent.), and very rarely from the internal or external iliac. Portal found 

 in one instance the right and left renal arteries arising by a common trunk from the fore 

 part of the aorta. 



The branches of the renal artery, or an accessory artery, instead of entering at the hilum, 

 sometimes reach and penetrate the gland near its upper or lower end, or on its anterior 

 surface. The right renal artery has been seen to cross the vena cava in front instead of 

 behind. Supernumerary branches are also often found. The most frequent are the diaphrag- 

 matic arising in common with the inferior suprarenal, the middle suprarenal, the spermatic, 

 and one or more lumbar arteries. In rare instances a hepatic branch from the right renal, 

 branches to the large and small intestines, and to the pancreas have been observed. (A. 

 Macalister, " Multiple Renal Arteries," Journ. Anat., xvii, 1883; Report of Committee of 

 Collective Investigation of Anat. Soc., by Arthur Thomson, Journ. Anat., xxv, 1890.) 



Spermatic and ovarian arteries (v). The spermatic arteries of the male, 

 two small and very long vessels, arise close together from the fore part of the aorta 

 a little below the renal arteries. Each artery is directed downwards and somewhat 

 outwards immediately beneath the peritoneum, resting on the psoas muscle, that of 

 the right side passing also in front of the inferior vena cava ; it crosses obliquely 

 over the ureter and the lower part of the external iliac arterj r , and reaches the in- 

 ternal abdominal ring. There it comes into contact with the vas deferens, and 

 passes with the other constituents of the spermatic cord along the inguinal canal, 

 forming anastomoses with the cremasteric branch of the epigastric artery. Issuing 

 by the external abdominal ring, it descends to the scrotum, where it becomes tor- 

 tuous, and, approaching the back part of the testis, divides into branches which 

 pierce the fibrous capsule of that body. One or two branches ramify on the epidi- 

 dyinis and anastomose with the artery of the vas deferens. 



In the female, the ovarian arteries, corresponding to the spermatic arteries in 

 the male, are shorter than these vessels, and do not pass out of the abdominal cavity. 

 The origin, direction, and relations of the artery in the first part of its course are 

 the same as in the male ; but at the margin of the pelvis it inclines inwards, and, 

 running tortuously between the layers of the broad ligament of the uterus, is guided 

 to the attached margin of the ovary, which it supplies with branches. One small 

 offset extends along the round ligament into the inguinal canal, another along the 

 Fallopian tube, and a third, of considerable size, running inwards towards the uterus, 

 joins with the uterine artery. During pregnancy the ovarian artery becomes con- 

 siderably enlarged. 



In early foetal life the spermatic and ovarian arteries are short, as the testes and the 

 ovaries are at first placed close to the kidneys, but the arteries become lengthened as these 

 organs descend to their ultimate positions. Small branches to the subperitoneal tissue are 

 given off from the spermatic artery throughout its course, and those arising in the lower part 

 of the abdomen take a recurrent direction in consequence of the shifting of their place of 

 origin with the elongation of the parent vessel (C. B. Lockwood, " Development and 

 Transition of the Testis," Journ. Anat., xxii, 1888). 



Varieties. The spermatic artery is frequently derived from the renal, occasionally from 

 the suprarenal, on one side. The right and left arteries occasionally arise by a common 

 trunk. Two spermatic arteries are not unfrequently met with on one side ; both of these 

 usually arise from the aorta, though sometimes one is a branch of the renal artery. A case 

 has occurred of three arteries on one side, two from the aorta and the third from the 

 renal (R. Quain). 



