| MEC | median effective concentration; middle ear canal; middle ear cell; minimum effective concentration |
|---|---|
| PC | avoirdupois weight [Lat. pondus civile]; packed cells; paper chromatography; paracortex; parent cell... |
| RC | an electronic circuit containing a resistor and capacitor in series; radiocarpal; reaction center; r... |
| RCT | radiotherapy and chemotherapy; randomized clinical trial; randomized controlled trial; registered ca... |
| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
| principal optic axis | A line passing through the centre of the lens of a refracting system at right angles to its surface. (05 Mar 2000) |
|---|---|
| septo-optic dysplasia | <radiology> Blindness, hypopituitarism, hypoplastic optic nerves, optic chiasm rotated 90 degrees, bulbous 3rd ventricle, CT findings: absent septum pellucidum, small optic nerves (12 Dec 1998) |
| neural layer of optic retina | See: retina. (05 Mar 2000) |
| neuroma, optic | A benign tumour of the optic nerve. (12 Dec 1998) |
| depression of optic disk | 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) |
| drusen of the optic nerve head | Basophilic, laminated, calcareous acellular masses that resemble crystals within the nerve head, anterior to the lamina cribrosa, that may simulate papilledema and/or cause visual field defects. Synonym: intrapapillary drusen. (05 Mar 2000) |
| dural 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) |
| internal sheath of optic nerve | <anatomy, nerve> The innermost sheath around the optic nerve, continuous with the leptomeninges (pia-arachnoid) and including a cerebrospinal fluid-filled intervaginal space, continuous with the subarachnoid space. Synonym: vagina interna nervi optici. (05 Mar 2000) |
| intersheath spaces of optic nerve | <anatomy, nerve> The spaces within the internal sheath of the optic nerve, between the arachnoidal and pial layers, filled with cerebrospinal fluid and continuous with the subarachnoid space. Synonym: spatia intervaginalia nervi optici, intersheath spaces of optic nerve, Schwalbe's spaces. (05 Mar 2000) |
| intervaginal space of optic nerve | <anatomy, nerve> The spaces within the internal sheath of the optic nerve, between the arachnoidal and pial layers, filled with cerebrospinal fluid and continuous with the subarachnoid space. Synonym: spatia intervaginalia nervi optici, intersheath spaces of optic nerve, Schwalbe's spaces. (05 Mar 2000) |
| intracanicular part of optic nerve | <anatomy, nerve> The part of the optic nerve lying within the optic canal. Synonym: pars intracanaliculus nervi optici. (05 Mar 2000) |
| intracranial part of optic nerve | <anatomy, nerve> The portion of the optic nerve between the optic canal and the optic chiasm. Synonym: pars intracranialis nervi optici. (05 Mar 2000) |
| intralaminar part of optic nerve | <anatomy, nerve> The portion of the optic nerve as it passes through the lamina cribrosa of the sclera. Synonym: pars intralaminaris nervi optici. (05 Mar 2000) |
| intraocular part of optic nerve | <anatomy, nerve> The part of the optic nerve within the eye; it is divided into intralaminar, postlaminar, and prelaminar parts. Synonym: pars intraocularis nervi optici. (05 Mar 2000) |
| ischemic optic neuropathy | Optic nerve neuropathy secondary to hypoperfusion of the low pressure posterior ciliary arteries supplying the optic nerve head (nonarteritic) or to temporal arteritis (arteritic). (05 Mar 2000) |