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Middle cerebellar peduncle

The middle cerebellar peduncle is the largest of the three paired cerebellar peduncles, serving as a critical conduit between the cerebellum and the pons. Structurally robust and prominently lateral, it carries predominantly afferent fibers from the contralateral pontine nuclei to the cerebellum, making it essential for the integration of motor and sensory information. Its large, compact, and transverse orientation gives it a characteristic appearance on imaging and in gross anatomy, contributing to the distinctive outline of the cerebellar hemispheres.

Synonyms

  • Brachium pontis

  • Pontocerebellar tract (functionally related term)

  • Middle cerebellar pedunculus (alternate anatomical term)

Arterial Supply

  • Supplied mainly by branches of the anterior inferior cerebellar artery (AICA)

  • Additional minor contributions from the superior cerebellar artery (SCA)

  • Occasional supply from the basilar artery via perforating branches

Venous Drainage

  • Drains via the superior and inferior petrosal veins

  • Drains indirectly into the petrosal sinuses and then into the sigmoid sinus

  • Some drainage through the transverse sinus via cerebellar cortical veins

Function

  • Major afferent pathway: Transmits pontocerebellar fibers from the contralateral pontine nuclei to the cerebellum

  • Role in motor coordination: Integrates motor signals from the cerebral cortex, aiding in the fine-tuning and timing of voluntary movements

  • Involved in sensorimotor integration: Facilitates cerebellar processing necessary for balance, posture, and smooth execution of skilled movements

MRI Appearance

  • Appears as a large, homogenous, low-to-intermediate signal structure connecting the lateral aspect of the pons to the cerebellar hemisphere

  • T1-weighted images: Isointense to slightly hypointense compared to adjacent brainstem structures

  • T2-weighted images: Mildly hyperintense relative to white matter, well-demarcated

  • FLAIR images: Remains easily distinguishable, can be involved in demyelinating or inflammatory lesions (e.g., MS plaques)

  • DWI/ADC: Shows normal diffusion unless pathologically involved (e.g., infarction or glioma)

CT Appearance

  • Non-contrast CT: Appears as a symmetrical, iso- to hypodense area relative to the brainstem, with clear margins

  • Bone windows: Useful for delineating its anatomical relation to the petrous temporal bone

  • Pathological conditions: Edema, infarction, or tumors may cause focal hypoattenuation, swelling, or mass effect on adjacent cisterns

MRI images

Middle cerebellar peduncle MRI 3T axial image

MRI images

Middle cerebellar peduncle MRI 3T sagittal image

CT image

Middle cerebellar peduncle CT sag anatomy image -img-00001-00001