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.
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.