| orbital tubercle of zygomatic bone | A small elevation on the orbital surface of the zygomatic bone, just within the orbital margin, about 1 cm below the zygomaticofrontal suture; it gives attachment to the lateral check ligament, the lateral palpebral ligament, and the suspensory ligament of the eyeball. Synonym: eminentia orbitalis ossis zygomatici, orbital eminence of zygomatic bone, Whitnall's tubercle. (05 Mar 2000) |
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| orbital width | The distance between the dacryon and the farthest point on the anterior edge of the outer border of the orbit (Broca), or between the latter point and the junction of the frontolacrimal suture and the posterior edge of the lacrimal groove. (05 Mar 2000) |
| orbitale | In cephalometrics, the lowermost point in the lower margin of the bony orbit that may be felt under the skin. Origin: L. Of an orbit (05 Mar 2000) |
| orbitalis muscle | <anatomy> A rudimentary nonstriated muscle, crossing the infraorbital groove and sphenomaxillary fissure, intimately united with the periosteum of the orbit. Synonym: musculus orbitalis, Muller's muscle, orbital muscle. (05 Mar 2000) |
| orbitelae | <zoology> A division of spiders, including those that make geometrical webs, as the garden spider, or Epeira. Origin: NL, fr. L. Orbis an orb + tela a web. Source: Websters Dictionary (01 Mar 1998) |
| orbitofrontal artery | <anatomy, artery> A branch of the insular part of the middle cerebral artery distributed to the cortex of the lateral, inferior part of the frontal lobe. Synonym: arteria frontobasalis lateralis, ramus orbitofrontalis lateralis, lateral orbitofrontal branch, orbitofrontal artery. (05 Mar 2000) |
| orbitofrontal cortex | The cerebral cortex covering the basal surface of the frontal lobes. Synonym: fronto-orbital area. (05 Mar 2000) |
| orbitography | Radiographic evaluation of the orbit. Origin: L. Orbita, orbit, + G. Grapho, to write Positive contrast orbitography, orbitography with injection of a water soluble iodinated compound into the muscle cone or along the orbital floor. (05 Mar 2000) |
| orbitolites | <zoology> A genus of living Foraminifera, forming broad, thin, circular disks, containing numerous small chambers. Origin: NL. See Orbit, and -lite. Source: Websters Dictionary (01 Mar 1998) |
| orbitomeatal line | base line |
| orbitomeatal plane | A standard craniometric reference plane passing through the right and left porion and the left orbitale; drawn on the profile radiograph or photograph from the superior margin of the acoustic meatus to the orbitale. Synonym: auriculo-infraorbital plane, eye-ear plane, Frankfort horizontal plane, Frankfort plane, infraorbitomeatal plane. (05 Mar 2000) |
| orbitonasal | <anatomy> Of or pertaining to the orbit and the nose; as, the orbitonasal, or ophthalmic, nerve. Origin: Orbit + nasal. Source: Websters Dictionary (01 Mar 1998) |
| orbitonasal index | The ratio of the width between the lateral angles of the eyes, measured with a tape measure passing over the root of the nose times 100, to the width between the lateral angles of the eyes measured with a caliper. (05 Mar 2000) |
| orbitonometer | An instrument that measures the resistance offered to pressing the eyeball backwards into its socket. Origin: L. Orbita, orbit, + G. Metron, measure (05 Mar 2000) |
| orbitonometry | Measurement by means of the orbitonometer. (05 Mar 2000) |