| tympanic opening of eustachian tube | An opening in the anterior part of the tympanic cavity below the canal for the tensor tympani muscle. Synonym: ostium tympanicum tubae auditivae, tympanic opening of eustachian tube. (05 Mar 2000) |
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| tympanic part of temporal bone | The bony plate forming the greater part of the anterior wall of the bony part of the external acoustic meatus and the tympanic cavity and the posterior wall of the mandibular fossa. Synonym: pars tympanica ossis temporalis, tympanic part of temporal bone. (05 Mar 2000) |
| tympanic plate of temporal bone | The bony plate forming the greater part of the anterior wall of the bony part of the external acoustic meatus and the tympanic cavity and the posterior wall of the mandibular fossa. Synonym: pars tympanica ossis temporalis, tympanic part of temporal bone. (05 Mar 2000) |
| tympanic plexus | A plexus on the promontory of the labyrinthine wall of the tympanic cavity, formed by the tympanic nerve, an anastomotic branch of the facial, and sympathetic branches from the internal carotid plexus; it supplies the mucosa of the middle ear, mastoid cells, and auditory (eustachian) tube, and gives off the lesser superficial petrosal nerve to the otic ganglion. Synonym: plexus tympanicus, Jacobson's plexus. (05 Mar 2000) |
| tympanic promontory | A rounded eminence on the labyrinthine wall of the middle ear, caused by the first coil of the cochlea. Synonym: promontorium cavi tympani, tuber cochleae, tympanic promontory. (05 Mar 2000) |
| tympanic ring | In the foetus, a more or less complete bony ring at the medial end of the cartilaginous external acoustic meatus, to which is attached the tympanic membrane. Synonym: annulus tympanicus, tympanic bone. (05 Mar 2000) |
| tympanic sinus | A depression in the tympanic cavity posterior to the tympanic promontory. Synonym: sinus tympani. Sinus unguis, the deep cleft housing the root of the nail. Synonym: sinus of nail. (05 Mar 2000) |
| tympanic veins | Veins exiting from the tympanic cavity through the petrotympanic fissure with the chorda tympani and emptying into the retromandibular vein. Synonym: venae tympanicae. (05 Mar 2000) |
| tympanic wall of cochlear duct | The wall that separates the cochlear duct from the scala tympani; it consists of the osseous spiral lamina and the basilar membrane. Synonym: paries tympanicus ductus cochlearis, membrana spiralis, spiral membrane. (05 Mar 2000) |
| floor of tympanic cavity | The floor of the tympanic cavity; a thin plate of bone separating the tympanic cavity from the jugular fossa. Synonym: paries jugularis cavi tympani, fundus tympani, inferior wall of tympanic cavity, jugular wall of middle ear. (05 Mar 2000) |
| lateral wall of tympanic cavity | The wall formed mainly by the tympanic membrane. Synonym: paries membranaceus cavi tympani, lateral wall of middle ear, membranous wall of middle ear. (05 Mar 2000) |
| lesser tympanic spine | The posterior edge of the tympanic notch (of Rivinus). Synonym: spina tympanica minor. (05 Mar 2000) |
| A layer | <molecular biology> Right handed double helical DNA with approximately 11 residues per turn. Planes of base pairs in the helix are tilted 20 deg away from perpendicular to the axis of the helix. Formed from B DNA by dehydration. (18 Nov 1997) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| anterior elastic layer | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |