THE URETERS 



1359 



At its origin the right ureter is usually covered by the second part of the duodenum, and in its 

 course downward lies to the right of the inferior vena cava and is crossed by the right colic artery, 

 while near the pelvic brim it passes behind the lower part of the mesentery and the terminal 

 part of the ileum. The left ureter is crossed by the left colic 

 artery, and near the brim of the pelvis passes behind the 

 pelvic colon and its mesentery. 



The pelvic part runs at first downward on the lateral wall 

 of the pelvic cavity under cover of the peritoneum, lying in 

 front of the internal iliac vessels and on the inner side of the 

 impervious part of the hypogastric artery and the obturator 

 nerve and vessels. Opposite the lower part of the great 

 sacrosciatic foramen it inclines inward behind the vas def- 

 erens (which crosses to its inner side) and reaches the base 

 of the bladder, where in the male it is situated in front of the 

 upper end of the seminal Beside and at a distance of about 

 two inches from the opposite ureter. Finally, the ureters run 

 obliquely for about three-quarters of an inch through the 

 wall of the bladder and open by slit-like apertures into the 

 cavity of the viscus at the lateral angles of the trigone. 

 When the bladder is distended the openings of the ureters are 

 about two inches apart, but when it is empty and contracted 



the distance between them is diminished by one-half. Owing to their oblique course through 

 the coats of the bladder, their upper and lower walls become closely applied to each other when 

 the viscus is distended, and, acting as a valve, prevent regurgitation of urine from the bladder. 



In the female, the ureter forms, as it lies in relation to the wall of the pelvis, the posterior boun- 

 dary of a shallow depression named the ovarian fossa, in which the ovary is situated. It then 

 runs inward and forward on the lateral aspect of the cervix of the uterus and of the upper part 

 of the vagina to reach the base of the bladder. In this part of its course it is accompanied for 



FIG. 1106. Diagram showing 

 method of entrance of the ureter into 

 the bladder. (F. H. Gerrish.) 



RIGHT URETER PSOAS MUSCLE 



LEFT URETER 



ASCENDING 

 COLON 



APPENDIX (drawn 

 up under) 



ARTERIES OF 



SIG VOID 

 FLEXURE 



SUPERIOR 



HEMORRHOIDAl 



ARTERY 



ARTERY TO 



SIGMOID 



FLEXURE 



FIG. 1107. The relations of the pelvic mesocolon with the wall, the iliac, sigmoid, and superior hemorrhoidal 

 arteries, and the ureter. (Poirier and Charpy.) 



about an inch by the uterine artery, which then crosses in front of the ureter and ascends- between 

 the two layers of the broad ligament. The ureter is distant about three-quarters of an inch 

 from the lateral aspect of the neck of the uterus. 



The ureter is sometimes double, and the two tubes may remain distinct as far as the base of 

 the bladder. On rare occasions they open separately into the bladder cavity. 



