internal external iliac artery

3 min read 14-03-2025

The iliac arteries are major blood vessels that supply blood to the lower limbs and pelvic organs. They are crucial components of the systemic circulation and understanding their anatomy and function is vital in various medical fields. This article will delve into the internal and external iliac arteries, exploring their branching patterns, the regions they supply, and their clinical significance.

Anatomy of the Iliac Arteries

The common iliac arteries are formed by the bifurcation of the abdominal aorta at the level of the fourth lumbar vertebra. Each common iliac artery then divides into two branches: the internal iliac artery and the external iliac artery. This bifurcation typically occurs near the sacroiliac joint.

Internal Iliac Artery (Hypogastric Artery)

The internal iliac artery, also known as the hypogastric artery, is a shorter and thicker vessel compared to its external counterpart. It primarily supplies blood to the pelvic viscera and gluteal region. Its branching pattern is variable, but generally includes:

Anterior Division: This division supplies the pelvic viscera and includes branches like the umbilical artery, superior vesical artery, inferior vesical artery (in males), uterine artery (in females), vaginal artery (in females), middle rectal artery, internal pudendal artery, and obturator artery. The internal pudendal artery is particularly important, supplying blood to the external genitalia.
Posterior Division: This division primarily supplies the gluteal region and the posterior pelvic wall. Branches include the iliolumbar artery, lateral sacral arteries, and superior gluteal artery. The superior gluteal artery is the largest branch of the posterior division and plays a crucial role in supplying the gluteal muscles.

External Iliac Artery

The external iliac artery is a longer and more slender vessel. It continues inferiorly along the medial border of the psoas major muscle and passes deep to the inguinal ligament. Once it crosses the inguinal ligament, it becomes the femoral artery, the major artery supplying the lower limb. Before crossing the ligament, its primary branch is the inferior epigastric artery, which supplies the lower abdominal wall.

Clinical Significance

Understanding the anatomy and variations of the iliac arteries is crucial for various clinical procedures and diagnoses. Problems with these arteries can lead to several issues:

Atherosclerosis: Plaque buildup in the iliac arteries can narrow the vessels, reducing blood flow to the legs and pelvic organs. This can lead to peripheral artery disease (PAD), characterized by intermittent claudication (pain in the legs during exercise) and, in severe cases, critical limb ischemia (CLI).
Embolization: Blood clots can form in the iliac arteries and travel downstream, causing blockage in smaller arteries. This can lead to ischemia or infarction in the supplied tissues.
Trauma: Injuries to the pelvis can damage the iliac arteries, resulting in significant bleeding.
Interventional Radiology: Procedures like angioplasty and stenting are commonly performed on the iliac arteries to treat atherosclerosis and restore blood flow. Precise anatomical knowledge is crucial for the success of these interventions.
Surgical Procedures: Surgeons often need to ligate (tie off) or otherwise manipulate the iliac arteries during pelvic surgeries. A thorough understanding of their branching patterns is essential for avoiding complications.

Imaging Techniques

Various imaging techniques are used to visualize the iliac arteries, including:

Ultrasound: A non-invasive method used to assess blood flow and identify blockages.
CT angiography (CTA): Provides detailed three-dimensional images of the arteries and helps to identify areas of stenosis or occlusion.
Magnetic Resonance angiography (MRA): Another non-invasive technique offering excellent visualization of the iliac arteries.

Conclusion

The internal and external iliac arteries are vital vessels with distinct anatomical features and clinical significance. Their branching patterns, regional supplies, and potential pathologies must be well understood by medical professionals for accurate diagnosis and effective treatment of a wide range of conditions affecting the lower limbs and pelvic region. Further research and advancements in imaging techniques continue to enhance our understanding of these crucial arteries and improve patient care.