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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.
originally denoting either of the two halves of the midbrain (a relatively narrow "neck" connecting the forebrain to the hindbrain); this term has been variably used to designate only those large bundles of corticofugal fibers forming the crus cerebri or to designate the crus cerebri plus the midbrain tegmentum; this latter, more inclusive, usage (crus cerebri and midbrain tegmentum) is preferred by some; the substantia nigra, while a part of the base of the peduncle (basis pedunculi), is considered a structure separating the midbrain tegmentum from the crus cerebri.
See also: crus cerebri.
See also: crus cerebri.
Synonym(s): pedunculus cerebri [TA]