| 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) |
|---|---|
| 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) |
| orbiculare | Synonym: lenticular process of incus. Origin: L., fr. Orbiculus, a small disk (05 Mar 2000) |
| orbicularis | 1. Circular; denoting a circular or disk-shaped structure. Synonym: orbicularis muscle. Origin: L. Fr. Orbiculus, a small disk (05 Mar 2000) |
| orbicularis 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) |
| orbicularis oculi muscle | <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) |
| orbicularis oculi reflex | Contraction of the orbicularis oculi muscles upon tapping the margin of the orbit, or the bridge or tip of the nose. Synonym: nose-bridge-lid reflex, nose-eye reflex. (05 Mar 2000) |
| orbicularis oris | <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) |
| orbicularis phenomenon | A constriction of both pupils when an effort is made to close eyelids forcibly held apart. A variant of the pupil response to near vision. Synonym: Galassi's pupillary phenomenon, Gifford's reflex, lid-closure reaction, orbicularis phenomenon, orbicularis pupillary reflex, Piltz sign, Westphal's pupillary reflex, Westphal-Piltz phenomenon. (05 Mar 2000) |
| orbicularis pupillary reflex | A constriction of both pupils when an effort is made to close eyelids forcibly held apart. A variant of the pupil response to near vision. Synonym: Galassi's pupillary phenomenon, Gifford's reflex, lid-closure reaction, orbicularis phenomenon, orbicularis pupillary reflex, Piltz sign, Westphal's pupillary reflex, Westphal-Piltz phenomenon. (05 Mar 2000) |
| orbiculated | Made, or being, in the form of an orb; having a circular, or nearly circular, or a spheroidal, outline. <botany> Orbiculate leaf, a leaf whose outline is nearly circular. Origin: L. Orbiculatus. See Orbicular. Source: Websters Dictionary (01 Mar 1998) |
| orbiculus ciliaris | The darkly pigmented posterior zone of the ciliary body continuous with the retina at the ora serrata. Synonym: ciliary disk, ciliary ring, pars plana. Origin: Mod. L. (05 Mar 2000) |
| orbit | 1. <astronomy> The path described by a heavenly body in its periodical revolution around another body; as, the orbit of Jupiter, of the earth, of the moon. 2. An orb or ball. "Roll the lucid orbit of an eye." (Young) 3. <anatomy> The cavity or socket of the skull in which the eye and its appendages are situated. 4. <zoology> The skin which surrounds the eye of a bird. Origin: L. Orbita a track or rut made by a wheel, course, circuit, fr. Orbis a circle: cf. F. Orbite. See Orb. Source: Websters Dictionary (01 Mar 1998) |
| orbit evisceration | The surgical removal of the contents of the orbit. This includes the eyeball, blood vessels, muscles, fat, nerve supply, and periosteum. It should be differentiated from eye evisceration which removes the inner contents of the eye, leaving the sclera intact. (12 Dec 1998) |