1226 



SPLANCHNOLOGY 





The Ureter Proper measures from 25 to 30 cm. in length, and is a thick-walled 

 narrow cylindrical tube which is directly continuous near the lower end of the 

 kidney with the tapering extremity of the renal pelvis. It runs downward and 

 medialward in front of the Psoas major and, entering the pelvic cavity, finally 

 opens into the fundus of the bladder. 



The abdominal part (pars abdominalis) lies behind the peritoneum on the medial 

 part of the Psoas major, and is crossed obliquely by the internal spermatic vessels. 

 It enters the pelvic cavity by crossing either the termination of the common, or 

 the commencement of the external, iliac vessels. 



At its origin the right ureter is usually covered by the descending 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 and ileocolic vessels, while near the superior aperture 

 of the pelvis 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 vessels, and near the 

 superior aperture of the pelvis passes behind the sigmoid colon and its mesentery. 

 The pelvic part (pars pelmna] runs at first downward on the lateral wall of the 

 pelvic cavity, along the anterior border of the greater sciatic notch and under 

 cover of the peritoneum. It lies in front of the hypogastric artery medial to the 

 obturator nerve and the umbilical, obturator, inferior vesical, and middle hemor- 

 rhoidal arteries. Opposite the lower part of the greater sciatic foramen it inclines 

 medialward, and reaches the lateral angle of the bladder, where it is situated in 

 front of the upper end of the seminal vesicle and at a distance of about 5 cm. 

 from the opposite ureter; here the ductus deferens crosses to its medial side, and 

 the vesical veins surround it. Finally, the ureters run obliquely for about 2 cm. 

 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 5 cm. apart, but when it is empty and con- 

 tracted the distance between them is diminished by one-half. Owing to their 



oblique course through the coats 

 of the bladder, the upper and 

 lower walls of the terminal por- 

 tions of the ureters become closely 

 applied to each other when the 

 viscus is distended, and, acting as 

 valves, 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 bound- 

 ary of a shallow depression named 

 the ovarian fossa, in which the 

 ovary is situated. It then runs 

 medialward and forward on the 

 lateral aspect of the cervix uteri 

 and upper part of the vagina to 

 reach the fundus of the bladder. 

 In this part of its course it is ac- 

 companied for about 2.5 cm. 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 2 cm. from the side of the cervix of the uterus. The ureter is 

 sometimes duplicated on one or both sides, and the two tubes may remain 



&? ' Fibrous tissue 



Longitudinal 

 muscular fibers 



Circular muscular 

 fibers 



Subepithelial 

 connective tissuH 



Transitional 

 epithelium 



FIG. 1134. Transverse section of ureter. 



