| Cerebral peduncle | |
|---|---|
 Superficial dissection of brain-stem. Ventral view. ("cerebral peduncle" visible in red at center-right) | |
 Obtuse section (perpendicular to the brainstem) throughsuperior colliculus showing path ofoculomotor nerve (crus cerebri labeled at lower left). | |
| Details | |
| Identifiers | |
| Latin | pedunculus cerebri |
| MeSH | D065850 |
| NeuroNames | 487 |
| NeuroLex ID | birnlex_1202 |
| TA98 | A14.1.06.004 |
| TA2 | 5878 |
| FMA | 62394 |
| Anatomical terms of neuroanatomy | |
Thecerebral peduncles (In Latin,ped- means 'foot'.) are the two stalks that attach thecerebrum to thebrainstem.[1] They are structures at the front of themidbrain which arise from theventral pons and contain the large ascending (sensory) and descending (motor)tracts that run to and from thecerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are thecerebral cortex, thespinal cord and thecerebellum.[2] The region includes thetegmentum,crus cerebri andpretectum. By this definition, the cerebral peduncles are also known as thebasis pedunculi, while the large ventral bundle of efferent fibers is referred to as thecerebral crus (crus means ‘leg’ in Latin.) or thepes pedunculi (pes means 'foot' in Latin.).
The cerebral peduncles are located on either side of the midbrain and are the frontmost part of the midbrain, and act as the connectors between the rest of themidbrain and thethalamic nuclei and thus thecerebrum. As a whole, the cerebral peduncles assist in refining motor movements, learning new motor skills, and convertingproprioceptive information into balance and posture maintenance.[3][4] Importantfiber tracts that run through the cerebral peduncles are thecorticospinal,corticopontine, andcorticobulbar tracts.Damage to the cerebral peduncles results in unrefined motor skills, imbalance, and lack ofproprioception.[medical citation needed]
The descending upper fibers from theinternal capsule continue on through the midbrain and are then seen as the fibers in the cerebral peduncles.[5] The corticopontine fibers are found in the outer and inner third of the cerebral peduncle, these are the cortical input to the pontine nuclei.[6] The corticobulbar and corticospinal fibers are found in the middle third of the cerebral peduncle.[7] The corticospinal tract exits the internal capsule and is seen in the mid portion of the cerebral peduncles.
Cranial nerve III (oculomotor nerve) appears ventrally between the two cerebral peduncles in theinterpeduncular fossa. Cranial nerve IV (trochlear nerve) wraps around the lowest part of the cerebral peduncle.[8]
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