| anterior neuropore | The temporary opening at the extreme rostral (cephalic) end of the early embryonic forebrain; closes at the 20th somite stage. Synonym: anterior neuropore, cranial neuropore. (05 Mar 2000) |
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| anterior notch of cerebellum | A wide, shallow notch on the anterior surface of the cerebellum occupied laterally by the superior cerebellar peduncles and the inferior quadrigeminal bodies medially. Synonym: anterior notch of cerebellum, incisura cerebelli anterior, semilunar notch. (05 Mar 2000) |
| anterior notch of ear | A notch between the supratragic tubercle and the crus of the helix. Synonym: incisura anterior auris, anterior auricular groove, auricular notch, sulcus auriculae anterior. (05 Mar 2000) |
| anterior nuclei of thalamus | Collective term for three groups of nerve cells which together form the anterior thalamic tubercle: the anteroventral nuclei, a relatively large nucleus; the anteromedial nuclei; and the anterodorsal nuclei, a small (but large-celled) nucleus. The nuclei receive the mamillothalamic tract from the mamillary body, and additional afferents by way of the fornix; they project collectively to the cortex of the cingulate and parahippocampal gyrus. Synonym: nuclei anteriores thalami. (05 Mar 2000) |
| anterior occlusion | The occlusion of anterior teeth. Synonym: mesial occlusion. (05 Mar 2000) |
| anterior ocular segment | That portion of the eye comprising the cornea, iris, lens, and their associated chambers and adnexa. (05 Mar 2000) |
| anterior palatine arch | One of a pair of ridges or folds of mucous membrane passing from the soft palate to the side of the tongue; it encloses the palatoglossus muscle and forms anterior margin of the tonsillar fossa. Also demarcates oral cavity from isthmus of fauces. Synonym: arcus palatoglossus, anterior palatine arch, anterior pillar of fauces, arcus glossopalatinus, glossopalatine arch, glossopalatine fold. (05 Mar 2000) |
| anterior palatine foramen | An opening in the posterolateral corner of the hard palate opposite the last molar tooth, marking the lower end of the pterygopalatine canal. Synonym: foramen palatinum majus, anterior palatine foramen. (05 Mar 2000) |
| anterior parolfactory sulcus | A fissure marking the anterior border of the parolfactory area. Synonym: sulcus parolfactorius anterior. (05 Mar 2000) |
| anterior part | The portion of a structure that tlies most forward, or closest to the front surface relative to other parts; in human anatomy, the ventral portion of a structure. See: anterior part of anterior commissure of brain, anterior part of diaphragmatic surface of liver, anterior part of fornix of vagina. Synonym: pars anterior. (05 Mar 2000) |
| anterior part of diaphragmatic surface of liver | The part of the diaphragmatic surface of the liver deep to the costal arches and the xiphoid process. Synonym: pars anterior faciei diaphragmatis hepatis. (05 Mar 2000) |
| anterior part of fornix of vagina | The portion of the fornix of the vagina anterior to the uterine cervix. Synonym: pars anterior fornicis vaginae. (05 Mar 2000) |
| anterior part of pons | The large ventral part of the pons occupied by the nuclei pontis, traversed longitudinally by corticopontine, corticobulbar, and corticospinal fibres, and transversely by pontocerebellar fibres. Pontocerebellar fibres converging laterally form the middle cerebellar peduncle or brachium pontis. Synonym: pars ventralis pontis, anterior part of pons, basilar part of pons, pars basilaris pontis. (05 Mar 2000) |
| anterior pelvic exenteration | Removal of the urinary bladder, lower parts of the ureter, vagina, uterus, adnexa, and adjacent lymph nodes; a urinary diversion is necessary. (05 Mar 2000) |
| anterior perforated substance | A region at the base of the brain through which numerous small branches of the anterior and middle cerebral arteries (lenticulostriate arteries) enter the depth of the cerebral hemisphere; it is bordered medially by the optic chasm and anterior half of the optic tract, rostrally and laterally by the lateral olfactory stria; its anteromedial part corresponds to the olfactory tubercle. Synonym: substantia perforata anterior, locus perforatus anticus, olfactory area. (05 Mar 2000) |