Introduction to Internal Iliac Artery
- Six main arteries enter the lesser pelvis of females: the paired internal iliac and ovarian arteries, and the unpaired median sacral and superior rectal arteries.
- Since the testicular arteries do not enter the lesser pelvis, only four main arteries enter the lesser pelvis of males.
- The internal iliac artery is the principal artery of the pelvis, supplying most of the blood to the pelvic viscera and some to the musculoskeletal part of the pelvis; however, it also supplies branches to the gluteal region, medial thigh regions, and the perineum
- Each internal iliac artery (right or left) begins as a terminal branch of the common iliac artery, in front of the sacroiliac joint.
- 1. Each internal iliac artery (right or left) begins as a terminal branch of the common iliac artery, in front of the sacroiliac joint.
- 2. It runs downwards to reach the upper margin of the greater sciatic foramen.
- 3. Here, it divides into anterior and posterior trunks
The branches arising from the anterior trunk of the internal iliac artery are as follows:
- 1. The superior vesical arteryruns forwards and medially to supply the upper part of the urinary bladder.
a. The artery is crossed by the ductus deferens and may give a branch to it.
b. The stem of the artery represents the proximal part of the umbilical artery of the fetus. That is why it is continuous with the medial umbilical ligament that represents the distal obliterated part of the umbilical artery.
- 2. The inferior vesical artery (present only in the male) runs forwards and medially to supply the urinary bladder, the prostate, the seminal vesicle and the lower end of the ureter.
- In the female the inferior vesical artery is replaced by the vaginal artery that supplies the vagina, the urinary bladder and part of the rectum.
- 3.The middle rectal artery runs medially to reach the rectum, where it anastomoses with the superior and inferior rectal arteries. Apart from the rectum it supplies the seminal vesicles and the prostate.
- 4.The uterine artery (present in the female only) runs medially on the pelvic floor (formed by the levator ani) to reach the lateral side of the upper end of the vagina (lateral vaginal fornix).
- a. Leaving the pelvic wall it runs along the side of the uterus, within the two layers of the broad ligament to reach the junction of the uterus with the uterine tube.
- b. Finally it turns laterally (still within the broad ligament) to reach the hilum of the ovary. Here it anastomoses with the ovarian artery.
- c. Apart from branches to the uterus, the uterine tube, and to the ovary, it gives some branches to the vagina.
- 5. The obturator artery runs forwards and downwards on the lateral pelvic wall (formed here by obturator fascia covering the obturator internus).
a. It is accompanied by the obturator nerve (which lies above it) and the obturator vein (below it).
b. Reaching the obturator canal it passes through it to leave the pelvic cavity.
- 6. The internal pudendal artery supplies the external genitalia. It follows a complicated course.
- a. Starting within the pelvic cavity the artery passes out of it through the greater sciatic foramen to enter the gluteal region.
- b. After a short course in this region the artery passes through the lesser sciatic foramen to reach the lateral wall of the ischiorectal fossa.
- 7. The inferior gluteal artery begins within the pelvis where it lies anterior to the piriformis. It passes through the greater sciatic foramen, below the piriformis, to enter the gluteal region.
- The branches arising from the posterior trunk of the internal iliac artery are as follows:
- 1. The superior gluteal artery is the main continuation of the posterior trunk of the internal iliac artery. It leaves the pelvic cavity by passing through the greater sciatic foramen, above the piriformis muscle.
- 2. The lateral sacral arteries, superior and inferior, pass medially and divide into branches that pass through the anterior sacral foramina to supply the sacrum and related structures.
- 3. The iliolumbar artery arises from the posterior trunk of the internal iliac artery. It runs upwards and laterally and passes deep to the psoas major. Here it divides into a lumbar branch that supplies the psoas major and an iliac branch that supplies the iliacus and can be seen on its surface.
Other Anatomy Notes
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