The Ureters

The ureters are the narrow part of the excretory ducts of the kidneys. Each begins at the renal pelvis and terminates at the bladder. It is about ⅓ to ¼ inch (ca. 6 to 8 mm.) in diameter, and its average length is about 28 inches (ca. 70 cm.). The abdominal part (Pars abdominalis) of each ureter emerges ventrally from the hilus of the kidney, and curves backward and inward toward the lateral face of the posterior vena cava (right side) or the posterior aorta (left side). They then pass almost straight backward in the subperitoneal tissue on the surface of the psoas minor, cross the external iliac vessels, and enter the pelvic cavity. The pelvic part (Pars pelvina) passes backward and a little downward on the lateral wall of the pelvic cavity, turns inward, and pierces the dorsal wall of the bladder near the neck.

In the male the pelvic part enters the urogenital fold and crosses the vas deferens. In the female the ureter is situated in the greater part of its course in the dorsal part of the broad ligament of the uterus.

The wall of the ureter is composed of three coats. The outer fibrous coat (Tunica adventitia) is composed of loose fibrous tissue. The muscular coat (Tunica muscularis) consists of inner and outer layers of longitudinal fibers, with a stratum of circular fibers between them. The mucous membrane (Tunica mucosa) is covered with transitional epithelium; glands (Glandulæ mucosæ ureteris) resembling those of the renal pelvis occur in the first three or four inches of the ureter.