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Ureter
The ureters are muscular tubes, 2530 cm long, that connect the
kidneys to the urinary bladder. The ureter are retroperitoneal;
their superior
halves are in the abdomen (see Chapter 2) and their inferior
halves lie in the pelvis. As the ureter cross the bifurcation of
the common iliac artery or
the beginning of the external iliac artery (Fig. 3.14A) they
pass over the pelvic brim, thus leaving the abdomen and entering
the lesser pelvis. Thepelvic parts of the ureter run on the lateral
walls of the pelvis, parallel to the anterior margin of the greater
sciatic notch, between the parietal
pelvic peritoneum and the internal iliac arteries. Opposite the
ischial spine, they curve anteromedially, superior to the levator
ani, to enter the
urinary bladder. The inferior ends of the ureters are surrounded
by the vesical venous plexus (Fig. 3.13B & C). The ureters pass
obliquely through
the muscular wall of the urinary bladder in an inferomedial
direction, entering the outer surface of the bladder approximately
5 cm apart, but their
internal openings into the lumen of the empty bladder are
separated by only half that distance. This oblique passage through
the bladder wall
forms a one-way flap valve, the internal pressure of the filling
bladder causing the intramural passage to collapse. In addition,
contractions
of the bladder musculature act as a sphincter preventing the
reflux of urine into the ureters when the bladder contracts,
increasing internal
pressure during micturition. Urine is transported down the
ureters by means of peristaltic contractions, a few drops being
transported at intervals
of 1220 sec.
In males, the only structure that passes between the ureter and
the peritoneum is the ductus deferens (Fig. 3.14B); it crosses the
ureter within the
ureteric fold of peritoneum. The ureter lies posterolateral to
the ductus deferens and enters the posterosuperior angle of the
bladder, just superior
to the seminal gland.
In females, the ureter passes medial to the origin of the
uterine artery and continues to the level of the ischial spine,
where it is crossed superiorly
by the uterine artery (see clinical correlation [blue] boxes
Iatrogenic Injury of the Ureters during Ligation of Uterine Artery
andIatrogenic Injury of the Ureters during Ligation of Ovarian
Artery, in this chapter). It then passes close to the lateral part
of the fornix
of the vagina and enters the posterosuperior angle of the
bladder.
