| orbicular muscle of eye | <anatomy> Consists of three portions: orbital part, or external portion, which arises from frontal process of maxilla and nasal process of frontal bone, encircles aperture of orbit, and is inserted near origin; palpebral part, or internal portion, which arises from medial palpebral ligament, passes through each eyelid, and is inserted into lateral palpebral raphe; lacrimal part (tensor tarsi muscle, Duverney's or Horner's muscle) arises from posterior lacrimal crest and passes across lacrimal sac to join palpebral portion; action, closes eye, wrinkles forehead vertically; nerve supply, facial. Synonym: musculus orbicularis oculi, musculus orbicularis palpebrarum, orbicular muscle of eye, sphincter oculi. (05 Mar 2000) |
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| orbicular muscle | <anatomy> A sphincter-like sheet of muscle that encircles an orifice such as the mouth or the palpebral fissures. Synonym: musculus orbicularis, orbicular muscle, orbicularis. (05 Mar 2000) |
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| orbicular muscle of mouth | <anatomy, muscle> Origin, by nasolabial band from septum of the nose, by superior incisive bundle from incisor fossa of maxilla, by inferior incisive bundle from lower jaw each side of symphysis; insertion, fibres surround mouth between skin and mucous membrane of lips and cheeks, and are blended with other muscles; action, closes lips; nerve supply, facial. Synonym: musculus orbicularis oris, musculus sphincter oris, orbicular muscle of mouth, sphincter oris. (05 Mar 2000) |
| cochleo-orbicular reflex | A form of the wink reflex in which there is a contraction, sometimes very slight, of the orbicularis palpebrarum muscle when a sudden noise is made close to the ear; it is absent in labyrinthine disease with total deafness. Synonym: acousticopalpebral reflex, auropalpebral reflex, cochleo-orbicular reflex, startle reflex. (05 Mar 2000) |
| orbicular | Circular or nearly so. (09 Oct 1997) |
| orbicular bone | A knob at the tip of the long limb of the incus which articulates with the stapes. Synonym: processus lenticularis incudis, lenticular apophysis, lenticular bone, orbicular bone, orbicular process, orbiculare, os orbiculare, os sylvii. (05 Mar 2000) |
| orbicular ligament | <anatomy> One of a number of ligament's encircling various parts; the principal annular ligament's are those of the stapes, radius, and trachea. See: annular ligament of the radius, annular ligament of the stapes, annular ligaments of the trachea. Synonym: ligamentum annulare, orbicular ligament. (05 Mar 2000) |
| orbicular ligament of radius | The ligament that encircles and holds the head of the radius in the radial notch of the ulna, forming the proximal radioulnar joint and enabling pronation/supination of forearm; receives the radial collateral ligament of the elbow. Synonym: ligamentum annulare radii, ligamentum orbiculare radii, orbicular ligament of radius. (05 Mar 2000) |
| orbicular process | A knob at the tip of the long limb of the incus which articulates with the stapes. Synonym: processus lenticularis incudis, lenticular apophysis, lenticular bone, orbicular bone, orbicular process, orbiculare, os orbiculare, os sylvii. (05 Mar 2000) |
| orbicular zone | Fibres of the articular capsule of the hip joint encircling the neck of the femur. Synonym: orbicular zone, ring ligament, zonular band. (05 Mar 2000) |
| accessory organs of the eye | The eyelids, with lashes and eyebrows, lacrimal apparatus, conjunctival sac, and extrinsic muscles of the eyeball. Synonym: organa oculi accessoria, accessory organs, accessory visual apparatus, adnexa oculi, appendages of eye. (05 Mar 2000) |
| accommodation of eye | The increase in thickness and convexity of the eye's lens in order to focus the image of an external object upon the retina. (05 Mar 2000) |
| amaurotic cat's eye | A yellow reflex from the pupil in cases of retinoblastoma or pseudoglioma. (05 Mar 2000) |
| anterior chamber of eye | The space between the cornea anteriorly and the iris/pupil posteriorly, filled with a watery fluid (aqueous humor) and communicating through the pupil with the posterior chamber. Synonym: camera anterior bulbi, camera oculi anterior, camera oculi major. (05 Mar 2000) |
| anterior eye segment | That part of the eyeball anterior to the lens. (12 Dec 1998) |
| antibiotic eye drops | <pharmacology> A medication that is pH balanced to allow placement into the eye for the purpose of killing bacteria. Examples include: Bleph-10, Chloromycetin, Cortisporin-Ophthalmic, Gantrisin, Genoptic, Gentacidin, Garamycin, Gantrisin, Ilotycin, Sodium Sulamyd and Sulphair. (27 Sep 1997) |