| 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) |
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| 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 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) |
| 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) |
| 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) |
| uncinate process of ethmoid bone | A sickle-shaped process of bone on the medial wall of the ethmoidal labyrinth below the middle concha; it articulates with the ethmoidal process of the inferior concha and partly closes the orifice of the maxillary sinus. Synonym: processus uncinatus ossis ethmoidalis. (05 Mar 2000) |
| lateral mass of ethmoid bone | A mass of air cells with thin bony walls forming part of the lateral wall of the nasal cavity; the cells are arranged in three groups, anterior, middle, and posterior, and are closed laterally by the orbital plate which forms part of the wall of the orbit. Synonym: labyrinthus ethmoidalis, ectethmoid, ectoethmoid, lateral mass of ethmoid bone. (05 Mar 2000) |
| groove of pterygoid hamulus | A groove at the base of the hamular process which forms a pulley for the tendon of the tensor veli palatini muscle. Synonym: sulcus hamuli pterygoidei, sulcus of pterygoid hamulus. (05 Mar 2000) |
| hamulus | 1. <anatomy> A hook, or hooklike process. 2. <zoology> A hooked barbicel of a feather. Origin: L. Dim. Of hamus, hook (01 Mar 1998) |
| hamulus cochleae | The upper hooklike termination of the bony spiral lamina at the apex of the cochlea. Synonym: hamulus laminae spiralis, hamulus cochleae, hook of spiral lamina. (05 Mar 2000) |
| hamulus lacrimalis | The hooklike lower end of the lacrimal crest, curving between the frontal process and orbital surface of the maxilla to form the upper aperture of the bony portion of the nasolacrimal canal. Synonym: hamulus lacrimalis, hamular process of lacrimal bone. (05 Mar 2000) |
| hamulus laminae spiralis | The upper hooklike termination of the bony spiral lamina at the apex of the cochlea. Synonym: hamulus laminae spiralis, hamulus cochleae, hook of spiral lamina. (05 Mar 2000) |
| hamulus of spiral lamina | The upper hooklike termination of the bony spiral lamina at the apex of the cochlea. Synonym: hamulus laminae spiralis, hamulus cochleae, hook of spiral lamina. (05 Mar 2000) |
| hamulus ossis hamati | A hooklike process on the distal and medial part of the palmar surface of the hamate bone. Synonym: hamulus ossis hamati. (05 Mar 2000) |