External Iliac Artery

Overview

The external iliac artery is the larger terminal branch of the common iliac artery.

Origin

The common iliac artery bifurcates into the internal iliac artery and external iliac artery at the level of the pelvic brim, anterior to the sacroiliac joint.

Course

• Descends medial to the iliopsoas muscle

Termination

• Enters the thigh after passing the inguinal ligmanent, where it becomes the common femoral artery

Branches

• Deep circumflex iliac artery
  • Origin: Lateral side of the distal external iliac artery.
  • Course: Courses laterally along the superior border of the iliac crest
  • Supplies: Iliac fossa, transversus abdominis and internal oblique muscles
• Inferior epigastric artery
  • Origin: Medial side of the distal external iliac artery.
  • Course: Courses superiorly along the posterior surface of the inferior rectus abdominis
  • Supplies: Rectus abdominis. It may anastomoses with the superior epigastric artery (branch of internal thoracic artery, derived from first part of subclavian artery)

Development

• In the fourth week of gestation, the umbilical arteries anastomose with dorsal intersegmental artery branches to become the dominant placental-aortic connection.
• This umbilical artery then becomes the common and internal iliac artery after birth interrupts the placental circulation.
• At five weeks of gestation, the sciatic arteries and external iliac arteries arise from the same dorsal umbilical artery root. The two vessels then interconnect, and the sciatic artery regresses, forming the arteries of the lower extremity including the common femoral artery

Anatomical Variants

• Corona mortis – vascular connection between the obturator and external iliac or inferior epigastric vessel, which usually crosses the pubic ramus where it is vulnerable to injury
• Agenesis/Aplasia – this may be secondary to a persistent sciatic artery
• Persistent sciatic artery (complete or incomplete) – congenital vascular anomaly that can involve aplasia of the external iliac artery. Occurs when the sciatic artery is the primary blood supply to the lower extremity and the external iliac artery is absent. An incomplete persistent sciatic artery partially communicates with a hypoplastic ommon femoral artery. Patient may have absent femoral pulse with a palpable popliteal pulse.
• Arterial coiling/corkscrewing – age-related excessive elongation