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Obturator veins

The obturator veins are paired veins that accompany the obturator artery and nerve in the pelvis and thigh. They are important venous channels that drain blood from the medial thigh and communicate with both the pelvic venous system and the femoral venous system. Their anatomical course through the obturator canal makes them clinically significant in pelvic surgery, venous thrombosis, and as potential collateral channels in venous obstruction.

Synonyms

  • Veins of the obturator canal

  • Obturator venous plexus

  • Pelvic obturator veins

Course and Tributaries

  • Formation: The obturator vein is formed by the union of tributaries from the venous plexuses of the pelvis (including the vesical, prostatic, and uterine plexuses) and veins from the medial thigh muscles.

  • Course:

    • Ascends along the lateral pelvic wall, accompanying the obturator artery and nerve

    • Passes through the obturator canal to reach the thigh

    • Lies medial to the obturator artery in the canal

  • Termination: Drains into the internal iliac vein (often its anterior division).

Relations

  • Anteriorly: Pubic bone and obturator externus muscle

  • Posteriorly: Pelvic fascia and obturator internus muscle

  • Superiorly: Obturator artery and nerve

  • Inferiorly: Pelvic floor muscles

Function

  • Provides venous drainage of the medial thigh (adductor muscles, obturator externus)

  • Receives tributaries from pelvic venous plexuses (vesical, prostatic in males, uterine and vaginal in females)

  • Acts as a collateral channel between femoral and internal iliac venous systems

Clinical Significance

  • May be involved in pelvic venous thrombosis or extension of deep vein thrombosis (DVT) from lower limb veins

  • Important in pelvic surgeries, especially hysterectomy and pelvic lymphadenectomy, due to risk of injury and hemorrhage

  • Forms part of the corona mortis, an anastomotic connection between obturator and external iliac/femoral vessels, which can cause severe bleeding if damaged

  • Can provide collateral circulation in iliac vein obstruction

MRI Appearance

T1-weighted images:

  • Vein lumen shows low signal intensity when patent

  • Flow voids are typically seen in normal venous flow

T2-weighted images:

  • Lumen appears low signal with flow voids

  • Thrombosed vein shows intermediate-to-high signal intensity

STIR (Short Tau Inversion Recovery):

  • Patent veins remain dark

  • Thrombosed veins demonstrate bright signal intensity within lumen

T1 Fat-Sat Post-Contrast:

  • Patent vein enhances with contrast (opacified blood)

  • Thrombosed segment shows absence of enhancement; wall may enhance if inflamed

CT Appearance

Non-Contrast CT:

  • Veins appear as tubular soft tissue density structures along the lateral pelvic wall and obturator canal

  • Thrombosis may appear as hyperdense material in acute phase

Post-Contrast CT (CT Venography):

  • Veins opacify and enhance uniformly when patent

  • Thrombosed vein shows lack of enhancement with possible wall thickening

  • Pelvic varices or collateral veins may be visualized in venous obstruction

MRI image

Obturator veins MRI axial anatomy image-img-00000-00000_00001

MRI image

Obturator veins MRI axial anatomy image-img-00000-00000

CT image

Obturator veins CT axial anatomy image-img-00000-00000

CT image

Obturator veins CT axial anatomy image-img-00000-00000_00001