| perpendicular plate of ethmoid bone | A thin plate of bone projecting downward from the crista galli of the ethmoid; it forms part of the nasal septum. Synonym: lamina perpendicularis ossis ethmoidalis. (05 Mar 2000) |
|---|
| perpendicular plate | Flat portion of a bone which lies within or closely approximates a vertical plane. See: perpendicular plate of ethmoid bone, perpendicular plate of palatine bone. Synonym: lamina perpendicularis, pars perpendicularis, vertical plate. (05 Mar 2000) |
|---|---|
| perpendicular plate of palatine bone | The part of the palatine bone that extends vertically upward from the horizontal lamina; it forms part of the lateral wall of the nasal cavity. Synonym: lamina perpendicularis ossis palatini. (05 Mar 2000) |
| cribriform plate of ethmoid bone | A horizontal lamina from which are suspended the labyrinth, on either side, and the lamina perpendicularis in the centre; it fits into the ethmoidal notch of the frontal bone and supports the olfactory lobes of the cerebrum, being pierced with numerous openings for the passage of the olfactory nerves. Synonym: lamina cribrosa ossis ethmoidalis, cribrum, sieve bone, sieve plate. (05 Mar 2000) |
| orbital plate of ethmoid bone | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| perpendicular | 1. Exactly upright or vertical; pointing to the zenith; at right angles to the plane of the horizon; extending in a right line from any point toward the center of the earth. 2. <geometry> at right angles to a given line or surface; as, the line ad is perpendicular to the line bc. Perpendicular style, a name given to the latest variety of English Gothic architecture, which prevailed from the close of the 14th century to the early part of the 16th; probably so called from the vertical style of its window mullions. Origin: L. Perpendicularis, perpendicularius: cf. F. Perpendiculaire. See Perpendicle, Pension. 1. A line at right angles to the plane of the horizon; a vertical line or direction. 2. <geometry> A line or plane falling at right angles on another line or surface, or making equal angles with it on each side. Source: Websters Dictionary (01 Mar 1998) |
| perpendicular fasciculus | A bundle of association fibres running vertically and interconnecting regions of the temporal, occipital, and parietal lobes. (05 Mar 2000) |
| supra-ethmoid | <anatomy> Above, or on the dorsal side of, the ethmoid bone or cartilage. Source: Websters Dictionary (01 Mar 1998) |
| orbital lamina of ethmoid bone | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| orbital layer of ethmoid bone | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| ethmoid | <anatomy> The ethmoid bone. Source: Websters Dictionary (01 Mar 1998) |
| ethmoid air cells | The numerous small air-filled cells of the ethmoidal labyrinth. See: anterior ethmoidal air cells, middle ethmoidal air cells, posterior ethmoidal air cells. Synonym: cellulae ethmoidales, sinus ethmoidales, ethmoidal cells. (05 Mar 2000) |
| ethmoid angle | The angle made by the plane of the cribriform plate of the ethmoid bone extended to meet the basicranial axis. (05 Mar 2000) |
| ethmoid bone | An irregularly shaped bone lying between the orbital plates of the frontal and anterior to the sphenoid bone; it consists of two lateral masses of thin plates enclosing air cells, attached above to a perforated horizontal lamina, the cribriform plate, from which descends a median vertical or perpendicular plate in the interval between the two lateral masses; the bone articulates with the sphenoid, frontal, maxillary, lacrimal, and palatine bones, the inferior nasal concha, and the vomer; it enters into the formation of the anterior cranial fossa, the orbits, and the nasal cavity. Synonym: os ethmoidale. (05 Mar 2000) |
| ethmoid infundibulum | A passage from the middle meatus of the nose communicating with the anterior ethmoidal cells and frontal sinus. Synonym: infundibulum ethmoidale, ethmoid infundibulum. (05 Mar 2000) |
| ethmoid sinus | Numerous small thin-walled spaces or air cells in the ethmoid bone, where they form an ethmoidal labyrinth. (12 Dec 1998) |