

THE ABDOMINAL AORTA 



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they usually arise from the aorta, and may come off above or below the main artery, 

 the former being the more common position. Instead of entering the kidney at the 

 hilus, they usually pierce the upper or lower part of the gland. 



The internal spermatic arteries (aa. spermaticae interne; spermatic arteries} 

 (Fig. 531) are distributed to the testes. They are two slender vessels of consid- 

 erable length, and arise from the front of the aorta a little below the renal arteries. 

 Each passes obliquely downward and laterahvard behind the peritoneum, resting 

 on the Psoas major, the right spermatic lying in front of the inferior vena cava 

 and behind the middle colic and ileocolic arteries and the terminal part of the 

 ileum, the left behind the left colic and sigmoid arteries and the iliac colon. Each 

 crosses obliquely over the ureter and the lower part of the external iliac artery 



FIG. 53S. Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their 

 anastomoses. (From a preparation by Mr. Hamilton Drummond.) Prepared in same manner as Fig. 535. 



to reach the abdominal inguinal ring, through which it passes, and accompanies 

 the other constituents of the spermatic cord along the inguinal canal to the 

 scrotum, where it becomes tortuous, and divides into several branches. Two or 

 three of these accompany the ductus deferens, and supply the epididymis, anasto- 

 mosing with the artery of the ductus deferens ; others pierce the back part of the 

 tunica albuginea, and supply the substance of the testis. The internal spermatic 

 artery supplies one or two small branches to the ureter, and in the inguinal canal 

 gives one or two twigs to the Cremaster. 



The ovarian arteries (aa. ovariccp') are the corresponding arteries in the female 

 to the internal spermatic in the male. They supply the ovaries, are shorter than the 

 internal spermatics, and do not pass out of the abdominal cavity. The origin 

 and course of the first part of each artery are the same as those of the internal 





