THE URETERS—THE URINARY BLADDER 561 
THE URETERS 
The ureter is the narrow part of the excretory duct of the kidney. Each 
begins at the renal pelvis and terminates at the bladder. It is about 14 to 14 inch 
(ca. 6 to 8 mm.) in diameter, and its average length is about 28 inches (ca. 70 em.). 
The abdominal part (Pars abdominalis) of each ureter emerges ventrally from the 
hilus of the kidney, and curves backward and medially toward the lateral face of the 
posterior vena cava (right side) or the 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 ventrally on the lateral wall of the pelvic 
cavity, turns medially, and pierces the dorsal wall of the bladder near the neck. 
Inthe male the pelvic part enters the genital fold and crosses the ductus deferens. 
In the female the ureter is situated in most 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 external fibrous coat 
(Tunica adventitia) contains many elastic fibers. The muscular coat consists of 
internal and external layers of longitudinal fibers, with a stratum of circular fibers 
between them. The mucous membrane is covered with transitional epithelium; 
glands (Glandulz mucose ureteris) resembling those of the renal pelvis occur in the 
first three or four inches of the ureter. 
The blood-supply is derived from the renal and umbilical arteries. The nerves 
come from the solar and pelvic plexuses; many minute ganglia are present. 
THE URINARY BLADDER 
The urinary bladder (Vesica urinaria) (Figs. 366, 369, 370) differs in form, size, 
and position according to the amount of its contents. When empty and contracted, 
it is a dense, piriform mass, about the size of a fist, and lies on the ventral wall of 
the pelvic cavity at a variable distance behind the inlet. When moderately filled, 
it is ovoid in form, and extends a variable distance along the ventral abdominal wall. 
Its physiological capacity varies greatly, but may be estimated approximately at 
about three or four quarts. 
The anterior rounded blind end is termed the vertex; on its middle is a mass 
of cicatricial tissue (Centrum verticis), a vestige of the urachus, which in the fcetus 
forms a tubular connection between the bladder and the allantois. The middle 
part or body (Corpus vesic) is rounded, and is somewhat flattened dorso-ventrally, 
except when distended. It presents two surfaces, dorsal and ventral, the former 
being the more strongly convex, especially in its posterior part in front of the en- 
trance of the ureters.2 The posterior narrow extremity, the neck (Collum vesice), 
joins the urethra. 
The relations of the bladder vary according to the degree of fulness of the 
organ, and also differ in important respects in the two sexes. The ventral surface 
(Facies ventralis) lies on the ventral wall of the pelvis, and extends forward on the 
abdominal wall as the bladder fills. The dorsal surface (Facies dorsalis) in the male 
is related to the rectum, the genital fold, the terminal parts of the ductus 
deferentes, the vesicule seminales, and the prostate; in the female it is in contact 
instead with the body of the uterus and the vagina. The vertex of the full bladder 
has variable relations with coils of the small intestine and small colon, and the pelvic 
flexure of the large colon. 
Fixation— Displacement of the bladder is limited chiefly by three peritoneal 
1 This is often termed the fundus by veterinarians, but is not the homologue of the fundus of 
the human bladder. 
~ pis would correspond to the fundus vesic of man. 
