Medical Dictionary

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occipitofrontalis (ok-sip′i-to-frun-ta′lis)
See o. (muscle). [L.]

occipitomastoid (ok-sip′i-to-mas′toyd)
Relating to the occipital bone and the mastoid process.

occipitomental (ok-sip′i-to-men′tal)
Relating to the occiput and the chin.

occipitoparietal (ok-sip′i-to-pa-ri′e-tal)
Relating to the occipital and the parietal bones.

occipitotemporal (ok-sip′i-to-tem′po-ral)
Relating to the occiput and the temple, or the occipital and the temporal bones.

occipitothalamic (ok-sip′i-to-tha-lam′ik)
Relating to the nerve fibers leading from the occipital lobe of the cerebral cortex to the thalamus.

occiput, gen. occipitis (ok′si-put, ok-sip′i-tis) [TA]
The back of the head. [L.]

occlude (o-klood)
1. To close or bring together. 2. To enclose, as in an occluded virus. [see occlusion]

occluder (o-klood′er)
In dentistry, a name given to some articulators.

occlusal (o-kloo′zal)
1. Pertaining to occlusion or closure. 2. In dentistry, pertaining to the contacting surfaces of opposing o. units (teeth or occlusion rims) or the masticating surfaces of the posterior teeth.

occlusion (o-kloo′zhun)
1. The act of closing or the state of being closed. 2. In chemistry, the absorption of a gas by a metal or the inclusion of one substance within another (as in a gelatinous precipitate). 3. Any contact between the incising or masticating surfaces of the upper and lower teeth. 4. The relationship between the occlusal surfaces of the maxillary and mandibular teeth when they are in contact. [L. oc- cludo, pp. -clusus, to shut up, fr. ob., against, + claudo, to close] abnormal o. an arrangement of the teeth that is not considered to be within the normal range of variation. afunctional o. a malocclusion that does not permit normal function of the dentition. anterior o. 1. the o. of anterior teeth; 2. SYN: mesial o. (1) . balanced o. the simultaneous contacting of the upper and lower teeth on the right and left and in the anterior and posterior occlusal areas in centric and eccentric positions within the functional range; used primarily in reference to the mouth, but also arranged and observed on articulators, developed to prevent a tipping or rotating of the denture bases in relation to the supporting structures. SYN: balanced articulation, balanced bite. bimaxillary protrusive o. an o. in which both the maxilla and mandible protrude, causing the long axes of the maxillary anterior teeth to be at an extremely acute angle to the mandibular teeth; may be secondary to a skeletal or dental deformity, or both; seen commonly in blacks. buccal o. 1. malposition of a tooth toward the cheek; 2. the o. as seen from the buccal side of the teeth. centric o. 1. the relation of opposing occlusal surfaces that provides the maximum planned contact and/or intercuspation; 2. the o. of the teeth when the mandible is in centric relation to the maxillae. SYN: centric contact. coronary o. blockage of a coronary vessel, usually by thrombosis or atheroma, often leading to myocardial infarction. distal o. 1. a tooth occluding in a position distal to normal; SYN: disto-o., postnormal o., retrusive o. (2) . 2. SYN: distoclusion. eccentric o. any o. other than centric. edge-to-edge o. an o. in which the anterior teeth of both jaws meet along their incisal edges when the teeth are in centric o.. SYN: edge-to-edge bite, end-to-end bite, end-to-end o.. end-to-end o. SYN: edge-to-edge o.. functional o. 1. any tooth contacts made within the functional range of the opposing teeth surfaces; 2. o. that occurs during function. gliding o. SYN: dental articulation. hyperfunctional o. occlusal stress of tooth or teeth exceeding normal physiologic demands. labial o. 1. malposition of a tooth in a labial direction; 2. the o. as seen from the labial side of the arches. lateral o. malposition of a tooth or an entire dental arch in a direction away from the midline. lingual o. 1. SYN: linguoclusion. 2. interdigitation of the teeth as seen from the internal or lingual aspect. mechanically balanced o. a balanced o. without reference to physiologic considerations, as on an articulator. mesenteric artery o. obstruction of arterial flow in the mesenteric circulation by an embolus or thrombus; usually refers to o. of the superior mesenteric artery, although atherosclerotic narrowing may involve all three major splanchnic branches (celiac, superior, and inferior mesenteric). mesial o. 1. o. in which the mandibular teeth articulate with the maxillary teeth in a position anterior to normal; SYN: anterior o. (2) , mesio-o.. 2. SYN: mesioclusion. neutral o. 1. an arrangement of teeth such that the maxillary and mandibular first permanent molars are in normal anteroposterior relation; SYN: normal o. (2) . 2. SYN: neutroclusion. normal o. 1. that arrangement of teeth and their supporting structure that is usually found in health and that approaches an ideal or standard arrangement; SYN: normal bite. 2. SYN: neutral o. (1) . pathogenic o. an occlusal relationship capable of producing pathologic changes in the supporting tissues. physiologic o. o. in harmony with functions of the masticatory system. physiologically balanced o. a balanced o. that is in harmony with the temporomandibular joints and the neuromuscular system. posterior o. the most effective contact of the molar and bicuspid teeth of both jaws that allows for all the natural movements of the jaws essential to normal mastication and closure. SYN: posteroclusion. postnormal o. SYN: distal o. (1) . protrusive o. o. that results when the mandible is protruded forward from centric position. o. of pupil the presence of an opaque membrane closing the pupillary area. retrusive o. 1. a biting relationship in which the mandible is forcefully or habitually placed more distally than the patient's centric o.; 2. SYN: distal o. (1) . spherical form of o. an arrangement of teeth that places their occlusal surfaces on the surface of an imaginary sphere (usually 8 inches in diameter) with its center above the level of the teeth. SEE ALSO: Monson curve. torsive o. SYN: torsiversion. traumatic o. SYN: traumatogenic o.. traumatogenic o. a malocclusion capable of producing injury to the teeth and/or associated structures. SYN: traumatic o.. working o. SYN: working contacts, under contact.

occlusive (o-kloo′siv)
Serving to close; denoting a bandage or dressing that closes a wound and excludes it from the air.

occlusometer (ok-loo-som′e-ter)
SYN: gnathodynamometer.

occult (o-kult′, ok′ult)
1. Hidden; concealed; not manifest. 2. Denoting a concealed hemorrhage, the blood being inapparent or localized to a site where it is not visible. See o. blood. 3. In oncology, a clinically unidentified primary tumor with recognized metastases. [L. oc-culo, pp. -cultus, to cover, hide]

Oceanospirillum (o′shen-o-spi-ril′um)
A genus of motile, nonsporeforming, aerobic bacteria (family Spirillaceae) containing Gram-negative, rigid, helical cells that are 0.3–1.2 μm in diameter. Motile cells contain bipolar fascicles of flagella. There is no growth anaerobically with nitrate. These organisms are chemoorganotrophic and possess a strictly respiratory metabolism; they neither oxidize nor ferment carbohydrates; found in marine environments. There are at present five species in this genus, of which the type species is O. linum. [L. oceanus, ocean, + spirillum, coil]

ocellus, pl .ocelli (o-sel′us, -li)
1. The simple eye found in many invertebrates. SYN: eyespot (2) . 2. Facet of the compound eye of an insect. [L. dim. of oculus, eye]

ochlophobia (ok-lo-fo′be-a)
Morbid fear of crowds. [G. ochlos, a crowd, + phobos, fear]

Ochoa
Severo, Spanish-U.S. biochemist and Nobel laureate, 1905–1993. See O. law.

ochratoxin (o-kra-toks′ins)
A mycotoxin produced by Aspergillus ochraceus growing on stored cereal grains. Affects poultry and other animals fed the grain. o. A o. produced by some species of Aspergillus and Penicillium that can contaminate cereal grains and feeds, primarily following improper storage; a potent carcinogen in rodents.

Ochrobactrum (o-kro-bak′trum)
A Gram-negative genus of bacteria similar to Alcaligenes and Pseudomonas spp. in their distribution in environmental and water sources and their culture characteristics. These have been isolated from a number of clinical sources and appear to be a cause of nosocomial bacteremia.

ochrodermia (o-kro-der′me-a)
Yellow discoloration of the skin. [G. ochros, pale yellow, + derma, skin]

ochrometer (o-krom′e-ter)
An instrument for determining the capillary blood pressure; one of two adjacent fingers is compressed by a rubber balloon until blanching of the skin occurs, after which the force necessary to accomplish this color change is read in millimeters of mercury. [G. ochros, pale yellow, + metron, measure]

ochronosis (o-kron-o′sis)
A rare, autosomal recessive disease characterized by alkapton uria with pigmentation of the cartilages and sometimes tissues such as muscle, epithelial cells, and dense connective tissue; may affect also the sclera, mucous membrane of the lips, and skin of the ears, face, and hands, and cause standing urine to be dark-colored and contain pigmented casts; pigmentation is thought to result from oxidized homogentisic acid, and cartilage degeneration results in osteoarthritis, particularly of the spine. [G. ochros, pale yellow, + nosos, disease] exogenous o. pigmentation of the skin of the face and elsewhere from prolonged topical exposure to hydroquinone-containing bleaching creams.

ochronotic (o-kron-ot′ik)
Relating to or characterized by ochronosis.

Ochsner
Albert John, U.S. surgeon, 1858–1925. See O. clamp, O. method.

ocrylate (ok′ri-lat)
A tissue adhesive for surgery.

oct-, octi-, octo-, octa-
Eight. [G. okto, L. octo]

OCTA (ok′ta)
An eight–base-pair sequence in DNA that has a regulatory role; for example, if it is artificially appended to a gene, it will cause that gene to be preferentially expressed in cells of the β-lymphocyte lineage.

octacosanoic acid (ok-ta-ko′san-o-ik)
A long-chain fatty acid; found in waxes. SYN: montanic acid.

octad (ok′tad)
1. SYN: octavalent. 2. An octavalent element or radical. [L. octo, eight]

octafluoropropane (ok′ta-flor′o-pro-pan)
A drug used for contrast enhancement during ultrasound imaging.

octamethyl pyrophosphoramide (OMPA) (ok-ta-meth′il pi′ro-fos-for′a-mid)
SYN: schradan.

octamylamine (ok-ta-mil′a-men)
An anticholinergic agent.

octan (ok′tan)
Applied to fever, the paroxysms of which recur every eighth day, the day of a paroxysm being counted as the first in the computation. [L. octo, eight]

octandioic acid
SYN: suberic acid.

octanoate (ok′ta-no′at)
SYN: caprylate.

octanoic acid (ok′ta-no′ik)
SYN: caprylic acid.

octanoyl-CoA synthetase (ok′tan-o-il sin′the-tas)
SYN: butyrate-CoA ligase.

octapeptide (ok′ta-pep′tid)
A peptide made up of eight amino acid residues.

octaploidy (ok′ta-ploy′de)
See polyploidy.

octapressin (ok′ta-pres′in)
SYN: felypressin.

octavalent (ok′ta-va′lent, ok-tav′a-lent)
Denoting a chemical element or radical having a combining power (valency) of eight. SYN: octad (1) .

octavus (ok-ta′vus)
SYN: vestibulocochlear nerve [CN VIII]. [L.]

octi-
See oct-.

octo-
See oct-.

Octomitidae (ok-to-mit′i-de)
A family in the protozoan class Zoomastigophorea; flagellates with six to eight flagella arranged in pairs and a body that is bilaterally symmetric; it includes the common human intestinal parasite G. lamblia. [octo- + G. mitos, thread]

Octomitus hominis (ok-tom′i-tus hom′i-nis)
Pentatrichomonas hominis.

octopamine (ok-to′pa-men)
A sympathomimetic amine; a false neurotransmitter produced by noradrenergic neurons in the presence of monoamine oxidase inhibitors. SYN: norsympatol, norsynephrine.

octose (ok′tos)
A sugar containing eight carbon atoms.

octoxynol (ok-tok′si-nol)
A surfactant.

octulose (ok′too-los)
An eight-carbon monoketose.

octulosonic acid (ok′too-lo-son′ik)
The -onic acid formally formed by oxidation of carbon atom 1 of octulose to a carboxylic acid group; a condensation product of d-arabinose and phosphoenolpyruvate analogous to neuraminic acid. It forms part of the repeating unit of the polysaccharides of the complex lipopolysaccharides of the Enterobacteriaceae constituting the characteristic somatic octose antigens.

octyl gallate (ok′til gal′at)
An antioxidant.

octylphenoxy polyethoxyethanol (ok′til-fe-nok′se pol′e-eth-ok′se-eth′a-nol)
Mono-p-isooctyl phenyl ether of polyethylene glycol; a surface-active (wetting) agent.

ocular (ok′u-lar)
1. SYN: ophthalmic. 2. The eyepiece of a microscope, the lens or lenses at the observer end of a microscope, by means of which the image focused by the objective is viewed. [L. oculus, eye] compensating o. an o. that compensates and corrects for the effects of chromatic aberration in the objective. Huygens o. the compound o. of a microscope, composed of two planoconvex lenses so arranged that the plane side of each is directed toward the observer. o. motor relating to or causing movements of the eyeball. Ramsden o. an eyepiece of a microscope, consisting of two planoconvex lenses with convexities turned to each other. wide field o. an o. that gives a larger than usual field of view and a high eyepoint.

ocularist (ok′u-lar-ist)
One skilled in the design, fabrication, and fitting of artificial eyes and the making of prostheses associated with the appearance or function of the eyes. [L. oculus, eye]

oculentum, pl .oculenta (ok-u-len′tum, -ta)
SYN: ophthalmic ointment. [Mod. L., fr. L. oculus, eye]

oculi (ok′u-li)
Plural of oculus. [L.]

oculist (ok′u-list)
SYN: ophthalmologist. [L. oculus, eye]

oculo-
The eye, ocular. SEE ALSO: ophthalmo-. [L. oculus]

oculoauriculovertebral (ok′u-lo-aw-rik′u-lo-ver′te-bral)
Relating to the eyes, ears, and vertebrae.

oculocardiac (ok′u-lo-kar′de-ak)
Relating to the eyes and heart.

oculocerebrorenal (ok′u-lo-ser′e-bro-re′nal)
Relating to the eyes, brain, and kidneys.

oculocutaneous (ok′u-lo-ku-ta′ne-us)
Relating to the eyes and the skin.

oculodentodigital (ok′u-lo-den′to-dij′i-tal)
Relating to the eyes, teeth, and fingers.

oculodermal (ok′u-lo-der′mal)
Relating to the eyes and skin.

oculodynia
Pain in the eyeball. SYN: ophthalmalgia. [ophthalmo- + G. algos, pain]

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