| lateral aperture of the fourth ventricle | One of the two lateral openings of the fourth ventricle into the subarachnoid space at the cerebellopontine angle. Synonym: apertura lateralis ventriculi quarti, foramen lateralis ventriculi quarti, foramen of Key-Retzius, foramen of Luschka, Retzius' foramen. (05 Mar 2000) |
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| fourth ventricle | A cavity of irregular tentlike shape extending from the obex rostralward to its communication with the sylvian aqueduct, enclosed between the cerebellum dorsally and the rhombencephalic tegmentum ventrally, having a rhomboid-shaped floor (rhomboid fossa) and a tentlike roof which in its caudal part is formed by the tela choroidea and the posterior medullary velum, in its middle part by the white matter of the cerebellum, and in its narrowing rostral part (recessus superior) by the anterior medullary velum. The fourth ventricle reaches its greatest width at the pontomedullary transition, where it expands laterally behind the cerebellar peduncles into the spoutlike lateral recess, and its greatest height at the fastigial recess, which reaches up into the cerebellar white matter. Direct communication of the brain's ventricle system and the subarachnoid space is established at the level of the fourth ventricle by a median opening in the tela choroidea, the medial aperture of Magendie's foramen, which opens into the cerebellomedullary cistern, and on both sides by the lateral aperture or foramen of Luschka, which connects the lateral recess with the interpeduncular cistern. Synonym: ventriculus quartus, ventricle of rhombencephalon. (05 Mar 2000) |
| fourth ventricle mass | <radiology> IN ADULTS: choroid plexus papilloma, haemangioblastoma, vermian metastasis, arteriovenous malformation (AVM), inflammatory mass/cyst IN KIDS: medulloblastoma, uniform enhancement, homogeneous, ependymoma, patchy enhancement, heterogeneous, calcified (12 Dec 1998) |
| lateral recess of fourth ventricle | The narrow recess of the ventricle that extends laterally over, and down along the side of, the inferior cerebellar peduncle and the overlying cochlear nuclei; at its tip it opens by way of Luschka's foramen into the interopeduncular cistern of the subarachnoid space. By way of this recess, part of the choroid plexus of the fourth ventricle protrudes into the subarachnoid space. Synonym: recessus lateralis ventriculi quarti. (05 Mar 2000) |
| arteria choroidea anterior | <anatomy, artery> Origin, internal carotid or (rarely) middle cerebral artery; distribution, optic tract, crus cerebri, uncus, hippocampus, globus pallidus, posterior part of internal capsule, geniculate bodies of the thalamus, and choroid plexus in the inferior horn of the lateral ventricle. Synonym: arteria choroidea anterior. (05 Mar 2000) |
| arteria choroidea posterior | <anatomy, artery> One of several choroid branches of the P2 segment of the posterior cerebral artery that supply the choroid plexus of the body of the lateral ventricle and of the third ventricle. Synonym: arteria choroidea posterior. (05 Mar 2000) |
| vena choroidea inferior | <anatomy, vein> A small vein draining the lower part of the choroid plexus of the lateral ventricle into the basal vein. Synonym: vena choroidea inferior. (05 Mar 2000) |
| vena choroidea superior | <anatomy, vein> A tortuous vein that follows the choroid plexus of the lateral ventricle and unites with the superior thalamostriate vein and the anterior vein of the transparent septum to form the internal cerebral vein. Synonym: vena choroidea superior. (05 Mar 2000) |
| choroidea | Synonym: choroid. Origin: see choroid (05 Mar 2000) |
| plica choroidea | In the embryo, an infolding of the chorion from which the choroid plexus develops. (05 Mar 2000) |
| tela | 1. Any thin weblike structure. 2. A tissue; especially one of delicate formation. Origin: L. A web (05 Mar 2000) |
| tela conjunctiva | <pathology> Rather general term for mesodermally derived tissue that may be more or less specialised. Cartilage and bone are specialised connective tissue, as is blood, but the term is probably better reserved for the less specialised tissue that is rich in extracellular matrix (collagen, proteoglycan etc.) and that surrounds other more highly ordered tissues and organs. (18 Nov 1997) |
| tela elastica | A form of connective tissue in which the elastic fibres predominate; it constitutes the ligamenta flava of the vertebrae and the ligamentum nuchae, especially of quadrupeds; it occurs also in the walls of the arteries and of the bronchial tree, and connects the cartilages of the larynx. Synonym: elastica, tela elastica. (05 Mar 2000) |
| tela subcutanea | A loose fibrous envelope beneath the skin, containing fat in its meshes (panniculus adiposus) or fasciculi of muscular tissue (panniculus carnosus); it contains the cutaneous vessels and nerves and is in relation by its undersurface with the deep fascia. Synonym: fascia superficialis, tela subcutanea, hypoderm, hypodermis, stratum subcutaneum, subcutis. (05 Mar 2000) |
| tela submucosa | A layer of tissue beneath a mucous membrane. The layer of connective tissue beneath the tunica mucosa. Synonym: tela submucosa, tunica submucosa. (05 Mar 2000) |