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Biventral lobule (HVIII) of cerebellum

The biventral lobule, also known as HVIII, is a cerebellar lobule located in the posterior inferior hemisphere of the cerebellum. It is part of the posterolateral cerebellar cortex and contributes to the vermal and hemispheric regions, lying adjacent to the tonsil and pyramis of the vermis. This lobule is involved in coordination of voluntary movements, posture, and fine motor control, particularly of the upper limbs and axial musculature.

The biventral lobule receives input from the pontocerebellar fibers, spinocerebellar tracts, and vestibulocerebellar pathways and projects to the deep cerebellar nuclei (interposed nuclei), integrating sensory and motor information for smooth, coordinated movement.

Function

  • Coordinates voluntary motor activity

  • Maintains balance and posture

  • Integrates sensory input from limbs and trunk for motor planning

  • Contributes to fine motor control, particularly of upper limbs

  • Plays a role in adaptive motor learning and cerebellar reflexes

Synonyms

  • HVIII

  • Biventral lobule of cerebellum

  • Posteroinferior cerebellar lobule

MRI Appearance

T1-weighted images:

  • Appears as gray matter isointense to cortex, forming part of the posterior inferior cerebellar hemisphere

  • Surrounded by white matter of the cerebellar arbor vitae, which is slightly hyperintense compared to gray matter

  • Lobule margins are well-delineated in sagittal and axial planes

T2-weighted images:

  • Cerebellar gray matter (including HVIII) is intermediate signal intensity

  • White matter arbor vitae appears relatively hypointense

  • CSF in the cerebellomedullary cistern appears hyperintense, providing contrast to the lobule

  • Useful for detecting edema, infarcts, or demyelinating lesions

STIR (Short Tau Inversion Recovery):

  • Normal lobule remains intermediate signal, while pathological edema or inflammation appears hyperintense

  • Sensitive for acute injury or demyelinating lesions

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal biventral lobule shows no significant enhancement

  • Abnormal enhancement may indicate tumor, inflammation, or demyelination

CT Appearance:

  • Appears as gray matter density within the posterior cerebellar hemisphere

  • White matter arbor vitae is slightly lower density, providing subtle contrast

MRI images

Biventral lobule, HVIII cerebellum of Cerebellum mri sag image -img-00000-00000