Cerebral peduncles

Last revised by Daniel J Bell on 15 Mar 2024

The cerebral peduncles are the anterior part of the midbrain that connects the brainstem to the thalami. They are paired, separated by the interpeduncular cistern, and contain the large white matter tracts that run to and from the cerebrum.


The crus cerebri (cerebral crus) usually refers to the most anterior, semilunar shaped bundle of white matter fibers in the midbrain, including the corticospinal tract centrally (3/5 intermediates) as well as the corticopontine (fronto-pontine and temporo-pontine fibers) and corticobulbar tracts. Posterior to the crus cerebri is the substantia nigra, followed by the mesencephalic tegmentum

"Cerebral peduncle" is commonly used synonymously with the crus cerebri alone 1,2, but traditionally this refers to the cylindrical shaped combination of the crus cerebri, substantia nigra, and tegmentum (i.e., the entire midbrain ventral to the tectum1-4.

The basis pedunculi or crusta traditionally refers to the combination of the crus cerebri and substantia nigra 3, but has also been used synonymously with the crus cerebri 2.

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