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Obturator vein

The obturator vein is the main venous companion of the obturator artery. It originates in the pelvic venous plexus surrounding the obturator internus and adductor muscles, then courses posteriorly along the lateral pelvic wall, and exits the pelvis through the obturator canal, accompanying the artery and nerve. It drains primarily into the internal iliac vein, though variations exist.

The obturator vein often has anastomotic connections with the external iliac vein or inferior epigastric vein. When such a large venous communication is present, it is known as the venous corona mortis, which is clinically important because injury may lead to life-threatening hemorrhage during pelvic or hernia surgery.

Synonyms

  • Vena obturatoria

  • Obturator venous tributary

  • Venous component of corona mortis (variant)

Function

  • Drains venous blood from the medial thigh muscles, hip joint capsule, and pelvic wall structures

  • Provides venous communication between internal and external iliac systems

  • Contributes to collateral venous drainage in cases of iliac vein obstruction

  • Clinical role in pelvic trauma, hernia repair, and varicose collateral formation

MRI Appearance

T1-weighted images:

  • Appears as a linear hypointense structure along pelvic wall and obturator canal

  • Surrounded by intermediate-signal pelvic fat for contrast

T2-weighted images:

  • Flowing blood: signal void

  • Thrombosed vein: intraluminal hyperintense signal with loss of normal void

  • Adjacent edema/inflammation also shows increased T2 signal

STIR:

  • Fat suppression enhances visualization of vein within pelvis

  • Thrombophlebitis or inflammation: perivenous edema appears bright

T1 Fat-Suppressed Post-Gadolinium:

  • Enhances brightly, outlining the course of the vein and its connections

  • Detects venous malformations, thrombosis with collateralization, or tumor invasion

MRV (Magnetic Resonance Venography):

  • Normal signal: flowing blood appears bright hyperintense with gadolinium

  • Thrombosis: seen as hypointense filling defect in otherwise bright enhancing vein

  • Depicts course from pelvic plexus through obturator canal into internal iliac vein

  • Excellent for preoperative mapping, thrombosis detection, and variant evaluation

CT Appearance

Non-contrast CT:

  • Obturator vein is difficult to visualize without contrast

  • May appear as tubular density in obturator canal, adjacent to artery and nerve

CT Post-Contrast:

  • Vein enhances along its pelvic course

  • Useful in identifying compression, displacement, or engorgement from pelvic masses

CTV (CT Venography):

  • Normal signal: vein lumen enhances as bright hyperdense structure

  • Thrombosis: appears as filling defect within enhancing vein

  • Shows venous corona mortis when present

  • Provides multiplanar and 3D mapping for surgical and trauma planning

MRI image

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MRI image

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MRI image

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CT image

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CT image

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CT image

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