Overview
This lecture covers the anatomy of the cerebellum, including its shape, location, subdivisions, surface features, deep nuclei, and blood supply.
Location & Structure
- The cerebellum is located in the posterior cranial fossa, mainly formed by the occipital bone.
- It sits posterior to the brainstem (midbrain, pons, medulla oblongata) and inferior to the cerebrum.
- Separated from the cerebrum by the tentorium cerebelli (a dural fold).
- The fourth ventricle lies at the midline, housing cerebrospinal fluid (CSF), draining via the median (Magendie) and lateral (Luschka) apertures.
- Attached to the brainstem by three cerebellar peduncles: superior, middle, and inferior.
Surface Anatomy & Lobes
- Composed of midline vermis and two lateral cerebellar hemispheres.
- Three main lobes: anterior, posterior, and flocculonodular.
- Vermis divided into nine lobules: lingula, central lobule, culmen, declive, folium, tuber, pyramid, uvula, and nodule.
- Lobules extend into hemispheres with different names (e.g., culmen becomes quadrangular lobule; uvula’s counterpart is tonsil).
Major Landmarks & Fissures
- Primary fissure separates anterior and posterior lobes.
- Horizontal fissure runs along the edge of the cerebellum.
- Pre-pyramidal fissure separates tuber and pyramid lobules.
Internal Organization
- Outer layer is gray matter; inner core is white matter.
- Surface has parallel folds called folia.
- Contains four deep cerebellar nuclei: dentate, emboliform, globose, and fastigial.
Blood Supply
- Supplied by three main arteries:
- Posterior inferior cerebellar artery (PICA) from the vertebral arteries.
- Anterior inferior cerebellar artery (AICA) from the basilar artery.
- Superior cerebellar artery from the distal basilar artery.
Key Terms & Definitions
- Vermis — midline structure connecting cerebellar hemispheres.
- Folia — fine, parallel folds on the cerebellar surface.
- Peduncles — white matter tracts connecting the cerebellum to the brainstem.
- Flocculonodular lobe — region involved in balance; composed of flocculus and nodule.
- Dentate nucleus — largest and most lateral deep cerebellar nucleus.
- Tonsil — inferior aspect of cerebellar hemisphere, counterpart to uvula.
Action Items / Next Steps
- Review labeled diagrams of cerebellar lobes and nuclei.
- Practice identifying cerebellar structures on MRI images.
- Study arterial blood supply routes to the cerebellum.