BLOOD SUPPLY OF UTERUS AND PELVIC ORGANS
With the exception of the ovarian, superior hemorrhoidal, and middle
sacral arteries, the hypogastric divisions of the common iliac arteries supply
the pelvic viscera.
The ovarian arteries arise from the aorta just below the origin of the renal vessels, at the same level at which the internal spermatic artery departs from the aorta in the male. The ovarian arteries course obliquely downward and laterally over the psoas major muscle and the ureter. They enter the true pelvis by crossing the common iliac artery just before its bifurcation. The ovarian artery enters the broad ligament at the junction of its superior and lateral borders. Continuing beneath the fallopian tube, it enters the mesovarium to supply the ovary. In addition to broad anastomoses with the ovarian rami of the uterine arteries, branches extend to the ampullar and isthmic portions of the tube, the ureter, and the round ligament.
The middle sacral artery is embryologically the continuation of the
aorta, which, owing to the strong development of the two common iliac arteries,
has become a very thin vessel. It passes in the midline downward over the
anterior surface of the fourth and fifth lumbar vertebrae, the sacrum and the
coccyx, and terminates in the glomus coccygeum, after giving off lumbar,
lateral, sacral, and rectal branches, which anastomose with branches of the
iliolumbar artery and supply muscular and bony structures of the posterior
pelvic wall.
The common iliac arteries are divisions of the abdominal aorta, which
bifurcates at the left side of the body of the fourth lumbar vertebra. An important
clinical landmark is that the right common iliac artery crosses anterior to the
left common iliac vein, which can unilaterally compress the iliac venous
system, resulting in relative venous stasis. This venous stasis increases the
risk of venous thrombosis in the left iliac venous system, known as the
May-Thurner syndrome. The common iliac arteries diverge and divide into the
external iliac and hypogastric (internal iliac) arteries. The ovarian vessels,
the ureter, and the sympathetic nerve fibers descending to the superior
hypogastric plexus cross the right common iliac artery. The left common iliac
artery, in addition, is covered by the sigmoid colon and mesocolon and by the
termination of the inferior mesenteric artery.
The external iliac artery is the larger of the two subdivisions of the
common iliac. It extends downward along the superior border of the true pelvis
to the lower margin of the inguinal ligament. It lies upon the medial border of
the psoas major muscle. Midway between the symphysis pubis and the anterior
superior iliac spine, it enters the thigh as the femoral artery.
The uterine artery arises from the anterior division of the hypogastric artery close to, or in common with, the middle hemorrhoidal or vaginal artery. It courses slightly forward and medialward on the superior fascia of the levatorani muscle to the lower margin of the broad ligament. The uterine artery, after entering the broad ligament, is surrounded in the parametrium by the uterine veins and a condensed sheath of connective tissue. It arches over the ureter about 2 cm lateral to the cervix. This topographic relationship is of extreme surgical importance. At the level of the isthmus, it gives off a descending cervical branch, which surrounds the cervix and anastomoses with branches of the vaginal artery. The main uterine vessels follow a tortuous course upward along the lateral margin of the uterus, giving off spiral branches to the anterior and posterior surfaces of the uterus. The uterine artery terminates in a tubal branch within the mesosalpinx, and an ovarian ramus, which anastomoses with the ovarian artery in the mesovarium.
