External and internal iliac artery

External Iliac Artery

Origin and Course

The external iliac artery originates from the bifurcation of the common iliac artery at the level of the fourth lumbar vertebra (L4). It descends along the medial border of the psoas major muscle and passes beneath the inguinal ligament to become the femoral artery, which supplies the lower limb .

Branches

1. Inferior Epigastric Artery: Arises just above the inguinal ligament, ascends within the transversalis fascia, and enters the rectus sheath to supply the anterior abdominal wall. It anastomoses with the superior epigastric artery
2. Deep Circumflex Iliac Artery: Arises near the inguinal ligament, runs laterally along the iliac crest between the transversus abdominis and internal oblique muscles, supplying the lateral abdominal wall .

Clinical Significance

• Kidney Transplantation: The external iliac artery is commonly used for vascular anastomosis in renal transplantation.
• Atherosclerosis: Susceptible to atherosclerotic changes, leading to peripheral arterial disease.
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🩺 Internal Iliac Artery

Origin and Course

The internal iliac artery, also known as the hypogastric artery, arises from the common iliac artery at the level of the lumbosacral junction (L5-S1). It descends into the pelvis and divides into anterior and posterior divisions, supplying pelvic organs, gluteal region, and perineum .

Branches

Posterior Division

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  Iliolumbar Artery: Ascends to supply the iliacus and psoas major muscles, as well as the lumbar vertebrae.
• Lateral Sacral Arteries: Descend along the sacrum, supplying sacral vertebrae and contents of the sacral canal.
• Superior Gluteal Artery: Exits the pelvis through the greater sciatic foramen above the piriformis muscle to supply the gluteal region.

Anterior Division

• Umbilical Artery: In the fetus, it carries blood to the placenta; postnatally, its proximal part remains patent as the superior vesical artery, supplying the bladder.
• Obturator Artery: Traverses the obturator canal to supply the medial thigh muscles .
• Inferior Vesical Artery (in males): Supplies the lower bladder, prostate, and seminal vesicles.
• Vaginal Artery (in females): Supplies the vagina and adjacent parts of the bladder and rectum.
• Uterine Artery (in females): Courses medially to supply the uterus; an important vessel in gynecological surgeries.
• Middle Rectal Artery: Supplies the rectum and anastomoses with superior and inferior rectal arteries.
• Internal Pudendal Artery: Exits the pelvis through the greater sciatic foramen, curves around the sacrospinous ligament, and re-enters through the lesser sciatic foramen to supply the perineum and external genitalia.
• Inferior Gluteal Artery: Exits below the piriformis muscle to supply the gluteal region and posterior thigh.

Mnemonics

• Posterior Division: "I Love Sex" — Iliolumbar, Lateral sacral, Superior gluteal.
• Anterior Division: "I Miss Our Underwear In Underwear, I Prefer Underwear" — Inferior vesical, Middle rectal, Obturator, Umbilical, Inferior gluteal, Internal pudendal, Uterine, Vaginal.

Clinical Significance

• Pelvic Hemorrhage Control: Ligation of the internal iliac artery can control pelvic bleeding.
• Aneurysms: Internal iliac artery aneurysms are rare but can cause significant complications if ruptured.

Visual Aids

For detailed anatomical illustrations, refer to the following resources:

• Kenhub: Provides comprehensive diagrams and explanations of the external and internal iliac arteries .
• Radiopaedia: Offers radiological images and descriptions of pelvic vasculature .

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References

• Kenhub. "External iliac artery: Anatomy and branches.
• Kenhub. "Internal iliac artery: anatomy, function, branches.
• Radiopaedia. "External iliac artery."
• Radiopaedia. "Internal iliac artery."
• Wikipedia. "Obturator artery."