middle cerebellar peduncle
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1. a stemlike connecting part.
2. a collection of nerve fibers connecting between different regions in the central nervous system.
3. the stalk by which a nonsessile tumor is attached to normal tissue. adj., adj pedun´cular.
cerebellar p's three sets of paired bundles (superior, middle, and inferior) connecting the cerebellum to the midbrain, pons, and medulla oblongata, respectively.
cerebral peduncle the anterior half of the midbrain, divisible into a posterior part (tegmentum) and an anterior part (crus cerebri), which are separated by the substantia nigra.
inferior cerebellar peduncle a large bundle of nerve fibers serving to connect the medulla oblongata and spinal cord with the cerebellum (especially the archicerebellum and paleocerebellum); it courses along the lateral border of the fourth ventricle and turns dorsally into the cerebellum. Formerly called caudal cerebellar peduncle.
middle cerebellar peduncle a large bundle of projection fibers originating in the contralateral pontine nuclei and entering the cerebellum, conveying impulses from the cerebral cortex to the neocerebellum.
pineal peduncle habenula (def. 2).
superior cerebellar peduncle a large bundle of projection fibers arising chiefly in the dentate nucleus of each cerebellar hemisphere (neocerebellum) and ascending to decussate in the mesencephalon; its fibers end mostly in the red nucleus and thalamus. Spinocerebellar fibers to the paleocerebellum lie adjacent to each peduncle. Formerly called rostral cerebellar peduncle.
p's of thalamus the four two-way radiations of thalamocortical fibers that connect the dorsal thalamus with many parts of the cerebral cortex, which together form a major portion of the internal capsule and the corona radiata.
mid·dle cer·e·bel·lar pe·dun·cle[TA]
the largest of three paired cerebellar peduncles, composed mainly of fibers that originate in the pontine nuclei, cross the midline in the basilar pons, and emerge on the opposite side as a massive bundle arching posteriorly along the lateral side of the pontine tegmentum into the cerebellum; there are some uncrossed pontocerebellar fibers in this peduncle; its fibers are distributed chiefly to the cortex of the cerebellar hemisphere with some collateral fibers passing to the cerebellar nuclei.
mid·dle cer·e·bel·lar pe·dun·cle(mid'ĕl ser-ĕ-bel'ăr pĕ-dŭnk'ĕl) [TA]
The largest of three paired cerebellar peduncles, composed mainly of fibers that originate in the pontine nuclei, cross the midline in the ventral part of pons, and emerge on the opposite side as a massive bundle arching dorsally along the lateral side of the pontine tegmentum into the cerebellum; its fibers are distributed chiefly to the cortex of the cerebellar hemisphere.
middle cerebellar peduncle
A thick band of axons running dorsally along the pontine (rostral) hindbrain and over the fourth ventricle to terminate in lateral regions of the cerebellar cortex. The middle cerebellar peduncle contains axons from the pontine nuclei; i.e., the pontocerebellar tract axons Synonym: brachium pontis
See also: peduncle