| orbital part of optic nerve | <anatomy, nerve> The part of the optic nerve between the eye and the optic canal. Synonym: pars orbitalis nervi optici. (05 Mar 2000) |
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| excavation of optic disc | The normally occurring depression or pit in the centre of the optic disc. Synonym: excavatio disci, depression of optic disk, excavatio papillae, physiologic cup, physiologic excavation. (05 Mar 2000) |
| external sheath of optic nerve | <anatomy, nerve> The outer sheath around the optic nerve, continuous with the dura mater. Synonym: vagina externa nervi optici, dural sheath of optic nerve. (05 Mar 2000) |
| Leber's hereditary optic atrophy | Hereditary degeneration of the optic nerve and papillomacular bundle with resulting rapid loss of central vision, progressive for several weeks, then usually stationary with permanent central scotoma; age of onset is variable, most often in the third decade; more males than females are affected and transmission is cytoplasmic and strictly on the female side. Mutation on the mitochondrial chromosome involved, which presumably interacts with an X-linked mutant. This mechanism may explain the bizarre sex ratio, which differs significantly from one country to another. (05 Mar 2000) |
| lenticulo-optic | Relating to the lentiform nucleus and the optic tract; specifically refers to branches of the middle cerebral artery considered to supply these structures. (05 Mar 2000) |
| alum root | <botany> A North American herb (Heuchera Americana) of the Saxifrage family, whose root has astringent properties. Source: Websters Dictionary (01 Mar 1998) |
| anatomical root | That portion of a tooth extending from the cervical line to its apical extremity. (05 Mar 2000) |
| angelica root | The root of Angelica archangelica (family Umbelliferae); a tonic and stimulant that may cause nausea; used as a carminative, diuretic, and externally as a counterirritant. (05 Mar 2000) |
| anterior root | The motor root of a spinal nerve. Synonym: radix anterior, radix motoria, anterior root, motor root, radix ventralis. (05 Mar 2000) |
| aquatic root | <plant biology> Roots that develop on stems above the normal position occupied by roots, in response to prolonged inundation with water. (09 Oct 1997) |
| arched root | <botany> Roots produced on the plant stems in a position above the normal position of roots, which serve to brace the plant during and following periods of prolonged inundation with water. (09 Oct 1997) |
| black root | <botany> Dried rhizome and roots of Veronicastrum virginicum (family Serophulariaceae). Indigenous to North America. Formerly used as a cathartic. Synonym: black root, Culver's root. (05 Mar 2000) |
| vandal root | <botany> Any plant of the genus Valeriana. The root of the officinal valerian (V. Officinalis) has a strong smell, and is much used in medicine as an antispasmodic. <botany> Greek valerian, a plant (Polemonium caeruleum) with blue or white flowers, and leaves resembling those of the officinal valerian. Origin: LL. Valeriana, perhaps from some person named Valerius, or fr. L. Valere to be strong. Powerful, on account of its medicinal virtues: cf. F. Valeriane. Source: Websters Dictionary (01 Mar 1998) |
| ganglion cells of dorsal spinal root | Pseudounipolar nerve cell bodies in the ganglia of the dorsal spinal nerve roots; the sensory spinal nerves are composed of the peripheral axon branches of these sensory ganglion cell's, whereas the central axon branch of each such cell enters the spinal cord as a component of the dorsal root. (05 Mar 2000) |
| ventral root | The motor root of a spinal nerve. Synonym: radix anterior, radix motoria, anterior root, motor root, radix ventralis. (05 Mar 2000) |