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Topic

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Inferior vermian vein

The inferior vermian vein is a midline posterior fossa vein that drains the inferior aspect of the cerebellar vermis. It courses posteriorly along the inferior vermis, often joining the inferior hemispheric veins before terminating in the great vein of Galen, straight sinus, or tentorial sinuses, depending on venous variation. It plays a vital role in draining venous blood from the posterior inferior cerebellar cortex and vermis. Venous anatomy in this region is highly variable, but recognition of the inferior vermian vein is important in posterior fossa surgery, venous infarction assessment, and neuroimaging interpretation.

Synonyms

  • Vein of inferior vermis

  • Cerebellar vermian vein (inferior)

  • Midline cerebellar vein

Function

  • Drains venous blood from the inferior cerebellar vermis

  • Contributes to posterior fossa venous circulation

  • Provides collateral drainage into the straight sinus, great vein of Galen, or tentorial sinuses

  • Plays a role in maintaining venous outflow balance in the posterior cranial fossa

MRI Appearance

T1-weighted images (non-contrast):

  • Appears as a linear hypointense (signal void) structure along the inferior vermis

  • Not well seen without angiographic sequences

T2-weighted images:

  • Also appears as a flow void (black linear structure)

  • Adjacent hyperintense parenchyma provides contrast

  • Thrombosed vein may appear hyperintense due to altered flow or clot signal characteristics

MRA / MR Venography:

  • Time-of-flight (TOF) or contrast-enhanced MRV depicts the course of the vein along the inferior vermis

  • Normal vein appears as a bright enhancing linear structure draining into the deep venous system

  • MRV is excellent for identifying venous variations, occlusion, or collateral drainage pathways

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Vein enhances brightly and homogeneously after contrast

  • Useful for detecting patency versus thrombosis

CT Appearance

Non-contrast CT:

  • Normally not well visualized

  • Acute thrombosis may present as a hyperdense venous structure in the posterior fossa

CT Angiography / CT Venography (CTV):

  • Clearly demonstrates the course of the inferior vermian vein and its drainage into the deep venous system

  • Opacified with contrast, appearing as a linear enhancing venous channel

  • Useful for detecting venous occlusion, malformations, or surgical planning

MRI images

Inferior vermian vein mri sag image