Vasculature - Arterial Supply Flashcards
Which major artery supplies the pelvic cavity?
Internal iliac artery.
Some minor small arteries also contribute to the supply.
At which vertebral level does the common iliac artery bifurcate?
L5-S1.
Anatomical relations to the internal iliac artery?
It is just medial to the external iliac and obturator nerve.
Which foramen does the internal iliac artery enter?
It enters at the superior border of the greater sciatic foramen, where it divides into anterior and posterior trunks.
What are the branches of the anterior division of the internal iliac artery?
This division gives supply to the perineum, gluteal and adductor regions of the lower limb.
1) Obturator artery - travels through the obturator canal, accompanied by the obturator nerve and vein. It supplies muyscles of the thigh’s adductor region.
2) Umbilical artery - gives rise to the superior vesical artery, which supplies the superior aspect of the urinary bladder.
- In utero, the umbilical artery transports deoxygenated blood from the fetus to the placenta.
3) Inferior vesical artery - supplies the lower aspect of the bladder. In males, it also supplies the prostate gland and seminal vesicles.
4) Vaginal artery (female) - descends to the vagina, supplying additional branches to the inferior bladder and rectum.
5) Uterine artery (female) - travels within the cardinal ligament to reach the cervix, where it ascends along the lateral aspect of the uterus. At origin of the fallopian tubes, it anastomoses with the ovarian artery. During its course, it crosses the ureters superiorly.
6) Middle rectal artery - travels medially to supply the distal part of the rectum. It also forms anastomoses with the superior rectal artery (derived from the inferior mesenteric) and the inferior rectal artery (derived from the internal pudendal).
7) Internal pudendal artery - moves inferiorly to exit the pelvis via the greater sciatic foramen. Accompanied by the pudendal nerve, it then enters the perineum via the lesser sciatic foramen. It then enters the perineum via the lesser sciatic foramen. It is the main artery responsible for the blood supply to the perineum.
8) Inferior gluteal artery - the terminal branch of the anterior trunk. It leaves the pelvic cavity via the greater sciatic foramen, emerging inferiorly to the piriformis muscle in the gluteal region. It contributes to the blood supply of the gluteal muscles and hip joint.
What are the branches of the posterior trunk of the internal iliac artery?
The posterior division gives rise to arteries that supply the lower posterior abdominal wall, posterior pelvic wall and the gluteal region. There are typically three branches:
1) Iliolumbar artery - ascends to exit the lesser pelvis, dividing into a lumbar and iliac branch supplies psoas major, quadratus lumborum and the posterior abdominal wall. The iliac branch supplies the muscles and bone around the iliac fossa.
2) Lateral sacral artery - travels infero-medially along the posterior pelvic wall to supply structures in the sacral canal, and the skin and muscle posterior to the sacrum.
3) Superior gluteal artery - the terminal branch of the posterior trunk. It exits the pelvic cavity via the greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle. It is the major blood supply to the muscles and skin of the gluteal region.
Minor arteries of the pelvis - gonadal arteries?
The ovarian artery is the major gonadal artery in females. It arises from the abdominal aorta, distal to the origin of the renal arteries. The artery descends towards the pelvis, crossing the pelvic brim and the origin of the external iliac vessels. It moves medially, dividing into an ovarian branch and tubal branches, which supply their respective structures.
Note - the testicular artery reaches the scrotum via the inguinal canal, and therefore does not actually enter the pelvis.
Minor arteries of the pelvis - medial sacral artery?
The median sacral artery originates from the posterior aspect of the abdominal aorta, at its bifurcation into the common iliac arteries. It descends anterior to the L4 and L5 vertebrae, the sacrum and the coccyx, contributing to the arterial supply of these regions.
Minor arteries of the pelvis - superior rectal artery?
The superior rectal artery is the terminal continuation of the inferior mesenteric artery. It crosses the left common iliac artery and descends in the mesentery of the sigmoid colon. It gives rise to branches that supply the rectum.
Clinical relevance - hysterectomy?
A hysterectomy is the surgical removal of the uterus. It has a number of possible indications. The following are the most common, but this is not an exhaustive list:
1) Heavy menstrual bleeding
2) Pelvic pain
3) Uterine prolapse (vaginal hysterectomy)
4) Gynaecological malignancy (usually ovarian, uterine or cervical)
5) Risk reducing surgery, usually in cases of BRCA 1 and 2 mutations, or Lynch syndrome.
When performing a hysterectomy, a good knowledge of regional anatomy is needed to prevent accidentally damaging other structures in the pelvic region.
The uterine artery crosses the ureters approximately 1cm laterally to the internal os of the cervix. Care must be taken not to damage the ureters during clamping of the uterine arteries during a hysterectomy. The relationship between the two can be remembered using the phrase, ‘water under the bridge’.
