| 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) |
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| 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) |
| left ventricle | <anatomy> The muscular chamber of the heart which accepts blood from the left atrium and ejects it into the aorta to the systemic circulation. (27 Sep 1997) |
| ala central lobule | The lateral winglike projection of the central lobule of the cerebellum. Synonym: ala lobuli centralis, ala cerebelli. (05 Mar 2000) |
| anterior central convolution | Bounded posteriorly by the central sulcus and anteriorly by the precentral sulcus. Synonym: gyrus precentralis, anterior central convolution, anterior central gyrus, ascending frontal convolution, ascending frontal gyrus. (05 Mar 2000) |
| anterior central gyrus | Bounded posteriorly by the central sulcus and anteriorly by the precentral sulcus. Synonym: gyrus precentralis, anterior central convolution, anterior central gyrus, ascending frontal convolution, ascending frontal gyrus. (05 Mar 2000) |
| anterolateral central arteries | Numerous small branches from the sphenoidal part of the middle cerebral arteries supplying the lateral and anterior parts of the corpus striatum. Synonym: arteriae centrales anterolaterales, arteriae thalamostriatae anterolaterales, anterolateral central arteries, anterolateral striate arteries, anterolateral thalamostriate arteries, arteries of cerebral haemorrhage, lenticulostriate arteries. (05 Mar 2000) |
| anteromedial central arteries | Several small branches of the precommunical part of the anterior cerebral artery; they are distributed to the anteromedial part of the corpus striatum part of the thalamus. Synonym: arteriae centrales anteromediales, arteriae thalamostriatae anteromediales, anteromedial thalamostriate arteries. (05 Mar 2000) |
| anteromedial central branches | Branches of the anterior communicating artery which supply part of the hypothalamus. Synonym: rami centrales anteromediales. (05 Mar 2000) |
| artery of central sulcus | <anatomy, artery> A branch of the terminal part of the middle cerebral artery distributed to the cortex on either side of the central sulcus. Synonym: arteria sulci centralis, artery of central sulcus, central artery, Rolandic artery. (05 Mar 2000) |
| asia, central | The geographical area of asia comprising kazakhstan, kyrgyzstan, tajikistan, turkmenistan, and uzbekistan. The desert region of kara kum (qara qum) is largely in turkmenistan and the desert region of kyzyl kum (kizil kum or qizil qum), is in uzbekistan and kazakhstan. (12 Dec 1998) |
| auditory diseases, central | Diseases of the auditory pathways from the bulbar cochlear nuclei to the auditory cortex in the temporal lobe. Structures involved include the medial and lateral lemnisci, inferior colliculus, and the medial geniculate nucleus. (12 Dec 1998) |
| recurrent central retinitis | An obsolete term for central serous retinopathy. (05 Mar 2000) |
| catheterization, central venous | Placement of an intravenous catheter in the subclavian, jugular, or other central vein for central venous pressure determination, chemotherapy, haemodialysis, or hyperalimentation. (12 Dec 1998) |
| measures of central tendency | General term for several characteristics of the distribution of a set of measurements or values around a value or values at or near the middle of the set; the principal measures of central tendency are mean, median, and mode. (05 Mar 2000) |