The external iliac vein is a major blood vessel located within the pelvis, playing a crucial role in the venous drainage of the lower limb and parts of the anterior abdominal wall. It is a paired vein, with one present on each side of the body.
Anatomy and Course
The external iliac vein begins at the inguinal ligament, where it is a direct continuation of the [[Femoral vein]]. From this point, it ascends superiorly and medially along the brim of the lesser pelvis, running alongside the [[External iliac artery]]. It passes through the pelvis, anterior to the sacroiliac joint. Posteriorly, it lies on the medial border of the psoas major muscle.
Typically, the right external iliac vein is positioned posterior to its corresponding artery, while the left external iliac vein is usually medial to its artery. As it reaches the level of the sacroiliac joint, it merges with the [[Internal iliac vein]] to form the [[Common iliac vein]]. This confluence usually occurs around the level of the fifth lumbar vertebra.
Tributaries
The primary tributaries of the external iliac vein, contributing to its volume of deoxygenated blood, include:
- [[Inferior epigastric vein]]: Drains blood from the anterior abdominal wall.
- [[Deep circumflex iliac vein]]: Drains blood from the iliac crest and anterior abdominal wall.
- Pubic vein (or obturator vein communications): Smaller veins that can drain from the pubic region and communicate with the obturator venous system.
- Occasionally, small veins draining the iliopsoas muscle or surrounding pelvic structures may also directly enter the external iliac vein.
Function
The primary function of the external iliac vein is to return deoxygenated blood from the entire [[Lower limb]] and significant portions of the [[Anterior abdominal wall]] and lower pelvic region back towards the heart. This blood then travels via the common iliac vein to the [[Inferior vena cava]].
Clinical Significance
- Deep Vein Thrombosis (DVT): The external iliac vein, along with the femoral and common iliac veins, is a common site for the formation of deep vein thrombi. A DVT in this location can lead to significant swelling of the entire lower limb and carries a risk of [[Pulmonary embolism]] if the clot dislodges and travels to the lungs.
- Central Venous Access: While less common than the subclavian or internal jugular veins, the external iliac vein can be accessed for central venous catheterization in certain clinical scenarios, particularly when other sites are unavailable or contraindicated.
- Surgical Procedures: Understanding the anatomy of the external iliac vein is critical during various pelvic and lower abdominal surgeries, such as lymphadenectomy for pelvic malignancies, vascular repair, or organ transplantation, to prevent injury and manage potential bleeding.
- Venous Compression Syndromes: Rarely, the external iliac vein can be compressed by adjacent structures, such as a hypertrophied psoas muscle or overlying arterial structures, leading to chronic venous outflow obstruction, similar to May-Thurner syndrome affecting the common iliac vein.
See Also
- [[Femoral vein]]
- [[Internal iliac vein]]
- [[Common iliac vein]]
- [[External iliac artery]]
- [[Inferior vena cava]]
- [[Deep Vein Thrombosis]]