Vasculature Of Ureters And Bladder
The blood supply of the ureters is variable and asymmetric. Indeed, any
nearby arteries that are primarily retroperitoneal or subperitoneal may provide
branches to the ureters.
In the abdomen, consistent ureteric branches arise from the renal
arteries, which supply the ureters either directly or via a branch to the renal
pelvis. Less consistent branches arise from the gonadal (testicular or ovarian)
arteries, common and external iliac arteries, or aorta. These branches extend
laterally to the abdominal ureter, which can thus undergo gentle medial
traction during surgery.
In the pelvis, consistent ureteric branches arise from the uterine
arteries in females and the inferior vesical arteries in males. Less consistent
branches arise from the gonadal (testicular or ovarian), superior vesical, or
internal iliac arteries. These branches extend medially to the pelvic ureter,
which can thus undergo gentle lateral traction during surgery. In this region,
the ureter is adherent to the posterior aspect of the serosa and thus also
receives small twigs from minor peritoneal arteries.
As all of these branches reach the ureter, they divide into ascending and
descending limbs that form longitudinal, anastomotic meshes on the outer ureter
wall. These meshes usually establish functional collateral circulation;
however, in approximately 10% to 15% of individuals, sufficient collaterals do
not form. Furthermore, ureteric branches are small and relatively delicate.
Thus disruption of these branches may lead to ischemia. During surgical
procedures, the location, disposition, and arterial supply of the ureters must
be carefully evaluated.
The distribution of ureteric veins follows that of the arteries. These
vessels drain to the renal vein; the inferior vena cava and its tributaries;
and the endopelvic venous plexuses.
Urinary Bladder
The arterial supply to the urinary bladder arises from the fanlike
ramification of the internal iliac vessels, usually from the anterior branches.
Although the branching pattern of the internal iliac vessels is variable, the
arteries that ultimately reach the bladder are quite consistent. In general,
two main arteries (or groups of arteries) may be distinguished:
1.
The superior vesical arteries each arise
as one or more branches of the patent umbilical arteries, usually just below
the level of the pelvic brim. Beyond the origin of these branches, the
umbilical arteries obliterate after birth, forming the medial umbilical
ligaments.
The superior vesical arteries provide the most constant
and significant blood supply to the bladder. The branches course over the body
and fundus of the bladder. They anastomose with each other, with their
contralateral fellows, and with branches of the inferior vesical arteries.
Their dynamic tortuosity and overall length allow for the changes in bladder
size that occur with filling and emptying. Superior vesical arteries may also
give rise to ureteric branches and, in males, to the deferential arteries. In
infants, a small urachal branch may extend toward the umbilicus, sometimes
anastomosing with the inferior epigastric arteries.
2.
The inferior vesical arteries may arise
as independent branches of the internal iliac arteries, in common with the
middle rectal arteries, or commonly in females from the uterine artery (directly
or via vaginal branches).
The inferior vesical arteries ramify over the fundus and neck of the
bladder. On their way to the bladder, the arteries pass through the lateral
ligaments of the bladder, where they usually give off ureteric branches and (in
the male) branches to the seminal glands (vesicles) and prostate. In males, the
inferior vesical arteries may give rise to the deferential arteries.
In some, the bladder receives additional branches from the obturator,
inferior gluteal, or internal pudendal arteries.
Vesical veins are short, uniting into a rich vesical venous plexus around
the base of the bladder. In males, this plexus is continuous with the prostatic
venous plexus.
The vesical plexus (or prostatic plexus in males) communicates with the
veins of the perineum, receiving the dorsal vein of the clitoris (or penis).
Multiple inter- connecting channels lead from the plexus to the internal iliac
veins. Anastomoses with the parietal veins of the pelvis establish connections
to the internal vertebral venous
plexus, thighs, and gluteal regions.
