| pineal habenula | The peduncle or stalk of the pineal gland. See: habenula. (05 Mar 2000) |
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| pineal recess | A diverticulum from the posterior part of the third ventricle extending back between the posterior commissure and the habenular commissure. Synonym: recessus pinealis. (05 Mar 2000) |
| pineal region tumours | Type of brain tumours. (12 Dec 1998) |
| pineal tumours | <radiology> SIGNS: aqueductal obstruction most likely to be hydrocephalus, paralysis of upward gaze (due to pressure on quarigeminal plate), precocious puberty, symptoms of hypothalamic, thalamic, cerebellar or pyramidal lesion TYPES: germ-cell (teratoid) tumours, teratoma, germinoma / atypical teratoma, endodermal sinus (yolk sac) tumour, choriocarcinoma, pineal-cell tumours, pineocytoma, pineo---, others, glioma, ganglioneuroma, ganglioglioma (12 Dec 1998) |
| superior cerebellar peduncle | A large bundle of nerve fibres that originate from the dentate and interpositus nuclei and emerges from the cerebellum in the rostral direction, along the lateral wall of the fourth ventricle. The bundle submerges from the dorsal surface of the brainstem into the mesencephalic tegmentum, where all of its fibres cross in the massive decussation of the superior cerebellar peduncles. Part of the bundle terminates in the contralateral red nucleus; the bulk of the fibres continue rostrally to parts of the ventral intermediate nucleus of thalamus, ventral posterolateral nucleus of thalamus, and central lateral nucleus of thalamus. Synonym: pedunculus cerebellaris superior, brachium conjunctivum cerebelli. (05 Mar 2000) |
| inferior cerebellar peduncle | Large paired bundles of nerve fibres which develop on the dorsolateral surfaces of the upper medulla, extend under the lateral recesses of the rhomboid fossa and curve dorsally into the cerebellum medial to the middle cerebellar peduncle; composed of a larger (lateral) bundle, the restiform body, and a small (medial) bundle, the juxtarestiform body. Fibres forming this composite bundle originate from spinal neurons and medullary relay nuclei. The largest constituent (restiform body) is crossed fibres from the inferior olive; it also contains the dorsal spinocerebellar tract and cerebellar projections from the lateral reticular nucleus, the accessory cuneate nucleus, the paramedian reticular nuclei and the perihypoglossal nuclei. Vestibulocerebellar fibres are placed medially in the inferior cerebellar peduncle and are usually separately identified as the juxtarestiform body. Synonym: pedunculus cerebellaris inferior. (05 Mar 2000) |
| inferior thalamic peduncle | A large fibre bundle emerging from the anterior part of the thalamus in the ventral direction, in part joining the medial fibres of the internal capsule, in other part curving laterally around the medial margin of the capsule into the innominate substance. Many of its fibres establish a reciprocal connection of the mediodorsal nucleus of the thalamus with the orbital gyri of the frontal lobe, but numerous other fibres constitute a conduction system from the amygdala and olfactory cortex to the mediodorsal nucleus. See: ansa peduncularis. Synonym: pedunculus thalami inferior. (05 Mar 2000) |
| olfactory peduncle | A nervelike, white band composed primarily of nerve fibres originating from the mitral cells and tufted cells of the olfactory bulb but also containing the scattered cells of the anterior olfactory nucleus. The tract is closely applied to the ventral surface of the frontal lobe, and attaches itself to the base of the cerebral hemisphere at the olfactory trigone, beyond which it extends in the form of the olfactory striae which distribute their fibres to the olfactory tubercle and, in largest number, to the olfactory cortex on and around the uncus of the parahippocampal gyrus. See: olfactory nerves. Synonym: tractus olfactorius, olfactory peduncle. (05 Mar 2000) |
| lateral thalamic peduncle | The massive group of fibres that emerges from the laterodorsal side of the thalamus to join the corona radiata; it reciprocally connects the lateral nucleus and the geniculate bodies of the thalamus with the corresponding regions of the cerebral cortex. Synonym: pedunculus thalami lateralis. (05 Mar 2000) |