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All parts of the brain › Compare two parts › Cerebrum vs cerebellum

Cerebrum vs cerebellum: where is each, and what is the difference?

The cerebrum is the largest part of the brain, the two cerebral hemispheres on top; the cerebellum (Latin for “little brain”) is tucked under the back of them, separated by a sheet of dura mater, the cerebellar tentorium. With the cerebellum’s help the cerebrum controls all voluntary actions; the cerebellum does not start movements, it fine-tunes their coordination, precision and timing. [1][2][3]

The 3D model has no one shape named the cerebrum, so its side here is the frontal, parietal, temporal and occipital lobes and the insula of both hemispheres, lit and measured as one set. The real cerebrum also holds deep parts such as the hippocampus and the basal ganglia, which this set leaves out. [1][4]

Measured from the model: the centre of the cerebellum is 65 mm from the centre of the cerebrum (both hemispheres) in a straight line [5].

The 3D brain needs JavaScript. The legend and the table below still say where each part is.

Slice

The cerebrum is lit in blue, the cerebellum in orange. Drag to turn, pinch or scroll to zoom; tap a part on the brain or in the legend to name it on its own; .

Side by side

Compared Cerebrum Cerebellum
Where it isThe uppermost region of the central nervous system: two roughly symmetric cerebral hemispheres, holding the cerebral cortex and deep parts such as the hippocampus and the basal ganglia. [1]In the posterior cranial fossa at the back of the base of the skull, under the cerebral hemispheres and on the back of the brainstem, below the cerebellar tentorium. [2][3][6]
What it doesThe centre of sensory perception, memory, thought and judgement, and of voluntary movement. [1]Does not start movements: it adds coordination, precision and accurate timing, comparing what the cerebrum commanded with feedback about what actually happened. [2][6]
Connects withThe two hemispheres are joined by the corpus callosum; motor neurons in the primary motor cortex send their axons down to the brainstem and spinal cord. [1]Three paired cerebellar peduncles; all its connections with the rest of the brain travel through the pons, and its main output runs through the thalamus to the cerebral cortex. [2]
Size measured from the model180 mm front to back, 117 mm top to bottom, 141 mm side to side [5]56 mm front to back, 53 mm top to bottom, 106 mm side to side [5]

Size is the box each part fits in on this one model (cerebrum (both hemispheres); cerebellum), not its volume. Real brains vary.

How far apart are they?

Measured from the model [5], from the cerebrum (both hemispheres) to the cerebellum:

  • Centre to centre: 65 mm in a straight line.
  • The centre of the cerebellum is 31 mm further back, 58 mm lower and the same distance from the midline than the centre of the cerebrum (both hemispheres).
  • Nearest points of the two shapes: about 1 mm apart.

A “centre” here is the average position of the points on the part’s 3D surface, so for a curved part such as a C shape it can sit outside the part itself. The nearest-points figure is measured between the corners of the simplified meshes, so a gap of 2 or 3 mm or less is within the model’s coarseness: read it as “touching or nearly so”.

How to tell them apart

  • The cerebellum takes up only about 10% of the brain’s volume, yet because of its many tiny granule cells it holds more neurons than all the rest of the brain together. [2]

Sources

  1. Wikipedia: Cerebrum
  2. Wikipedia: Cerebellum
  3. Wikipedia: Cerebellar tentorium
  4. Wikipedia: Lobes of the brain
  5. BodyParts3D 4.0 (3D model measured on this page), © DBCLS, CC BY-SA 2.1 Japan
  6. OpenStax Anatomy & Physiology 2e, 13.2 The Central Nervous System

Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain. Compare other pairs.