Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

orthoscope
(or´tho-skōp) an apparatus that neutralizes corneal refraction by means of a layer of water; used in ocular examinations.

orthoscopic
(or″tho-skop´ik) pertaining to orthoscopy or an orthoscope. having normal, undistorted vision. pertaining to an optical system that produces undistorted images.

orthoscopic lens
one that gives a flat and undistorted field of vision, especially at the periphery.

orthoscopy
(or-thos´kә-pe) examination by means of an orthoscope.

orthosis
(or-tho´sis) an orthopedic appliance or apparatus used to support, align, prevent, or correct deformities or to improve function of movable parts of the body. See also brace and splint.

orthostatic
(or″tho-stat´ik) pertaining to or caused by standing erect; see also orthostatic hypotension.

orthostatic proteinuria
a form of functional proteinuria, usually seen between the ages of ten and twenty, that occurs on standing erect and disappears on lying down.

orthostatic tachycardia
a type seen when a susceptible person rises from a reclining to a standing position.

orthostatism
(or´tho-stat″iz-әm) an erect standing position of the body.

orthotic
(or-thot´ik) serving to protect or to restore or improve function; pertaining to the use or application of an orthosis.

orthotics
(or-thot´iks) the field of knowledge relating to orthoses and their use.

orthotist
(or-thot´ist) a person skilled in orthotics and practicing its application in individual cases.

orthotonos
(or-thot´ә-nәs) tetanic spasm that fixes the head, body, and limbs in a rigid straight line.

orthotonos position
orthotonos.

orthotonus
(or-thot´ә-nәs) orthotonos.

orthotopic
(or″tho-top´ik) occurring at the normal place in the body. pertaining to a tissue transplant grafted into its normal place in the body.

orthotopic transplantation
transplantation of tissue from a donor into its normal position in the body of the recipient.

orthovoltage
(or´tho-vōl″tәj) in radiation therapy, voltage in the range of 140 to 400 kilovolts, as contrasted to supervoltage and megavoltage.

Ortner syndrome
(ort´ner) laryngeal paralysis associated with heart disease, due to compression of the recurrent laryngeal nerve between the aorta and a dilated pulmonary artery.

Ortolani sign
the presence of a palpable click in and out as the hip is reduced by abduction and dislocated by adduction in developmental dysplasia of the hip; called also Ortolani click.

Orungo virus
a mosquito-borne virus of the genus Orbivirus that causes a febrile illness in Nigeria and Uganda.

oryzoid bodies
rice bodies.

OS
abbreviation for Latin o´culus sinis´ter (left eye).

Os
osmium.

os
(os) Latin word meaning mouth or opening. In anatomy, it is used for any body orifice. the mouth. external os of uterus , os externum uteri the external opening of the uterine cervix into the vagina.

os
(os) Latin word meaning bone; a term used in anatomy.

Osborne wave
J wave.

oscillating vision
oscillopsia.

oscillation
(os″ĭ-la´shәn) a backward and forward motion, like that of a pendulum; called also vibration. See also fluctuation. high frequency oscillation a type of high frequency ventilation characterized by the use of active expiration.

oscillometer
(os″ĭ-lom´ә-tәr) an instrument for measuring oscillations.

oscillopsia
(os″ĭ-lop´se-ә) a visual sensation that stationary objects are swaying back and forth.

oscilloscope
(ә-sil´ә-skōp) an instrument that displays a visual representation of electrical variations on the fluorescent screen of a cathode-ray tube.

oscitation
(os″ĭ-ta´shәn) yawning.

osculum
(os´ku-lәm) a minute opening.

oseltamivir
(o″sәl-tam´ĭ-vir) an inhibitor of viral neuraminidase, used as the phosphate salt in the treatment of influenza.

Osgood-Schlatter disease
(oz´good shlah´tәr) osteochondrosis of the tuberosity of the tibia; called also Schlatter or Schlatter-Osgood disease.

OSHA
Occupational Safety and Health Administration.

Osler disease
(ōs´lәr) polycythemia vera. hereditary hemorrhagic telangiectasia.

Osler nodes
small, raised, swollen, tender areas, bluish or sometimes pink or red, due to inflammation around the site of lodgement of small infected emboli in distal arterioles; they occur commonly in the pads of the fingers or toes, in the palms, or in the soles and are practically pathognomonic for subacute bacterial endocarditis.

Osler sign
the presence of Osler nodes on the hands and feet, pathognomonic of subacute bacterial endocarditis.

Osler-Vaquez disease
(ōs´lәr vah-ka´) polycythemia vera.

Osler-Weber-Rendu disease
(ōs´lәr va´bәr ron-du´) hereditary hemorrhagic telangiectasia.

osmatic
(oz-mat´ik) olfactory.

osmidrosis
(oz″mĭ-dro´sis) bromhidrosis.

osmium
(Os) (oz´me-әm) a chemical element, atomic number 76, atomic weight 190.2.

osmolality
(oz″mo-lal´ĭ-te) the concentration of a solution in terms of osmoles of solutes per kilogram of solvent. serum osmolality a measure of the number of dissolved particles per unit of water in serum. In a solution, the fewer the particles of solute in proportion to the nu...

osmolar
(oz-mo´lәr) pertaining to the concentration of osmotically active particles in solution.

osmolarity
(oz″mo-lar´ĭ-te) the concentration of a solution in terms of osmoles of solutes per liter of solution.

osmole
(oz´mōl) a unit of osmotic pressure equivalent to the amount of solute that dissociates in solution to form one mole (Avogadro's number) of particles (molecules and ions). Symbol Osm.

osmometer
(oz-mom´ә-tәr) an instrument for measuring osmotic concentration or pressure.

osmophilic
(oz″mo-fil´ik) having an affinity for solutions of high osmotic pressure.

osmophobia
(oz″mo-fo´be-ә) irrational fear of odors.

osmophore
(oz´mo-for) the group of atoms in a molecule of a compound that is responsible for its odor.

osmoreceptor
(oz″mo-re-sep´tәr) any of a group of specialized neurons of the supraoptic nuclei of the thalamus that are stimulated by increased extracellular fluid osmolality to cause release of vasopressin by the neurohypophysis. olfactory receptor.

osmoregulation
(oz″mo-reg″u-la´shәn) adjustment of internal osmotic pressure of a simple organism or body cell in relation to that of the surrounding medium. adj., osmoreg´ulatory., adj.

osmose
(os´mōs) to diffuse by osmosis.

osmosis
(oz-mo´sis) (os-mo´sis) the diffusion of pure solvent across a membrane in response to a concentration gradient, usually from a solution of lesser to one of greater solute concentration. This process and the factors that influence it are important clinically for maintenance of adequate body fluids and p...

osmostat
(oz´mo-stat″) the regulatory centers that control the osmolality of the extracellular fluid.

osmotic diarrhea
a type due to the presence of osmotically active nonabsorbable solutes in the intestine, such as magnesium sulfate.

osmotic fragility
susceptibility of certain red blood cells to hemolysis when they are in increasingly hypotonic solutions; this is seen in some forms of hemolytic anemia and spherocytosis.

osmotic fragility test
(for spherocytosis) heparinized or defibrinated blood is placed in tubes of sodium chloride solution (pH 7.4) varying in concentration from 0.85 to 0.00 per cent (w/v); the amount of hemolysis in each tube is determined colorimetrically. Increased fragility indicates spherocytosis.

osmotic pressure
the pressure required to stop osmosis through a semipermeable membrane between a solution and a pure solvent; it is proportional to the osmolality of the solution. See discussion at osmosis. Symbol π.

ossein
(os´e-in) the collagen of bone.

osseocartilaginous
(os″e-o-kahr″tĭ-laj´ĭ-nәs) osteochondral.

osseofibrous
(os″e-o-fi´brәs) made up of fibrous tissue and bone.

osseointegration
(os″e-o-in″tә-gra´shәn) the formation of a direct interface between an orthopedic or dental implant and bone, without intervening soft tissue.

osseomucin
(os″e-o-mu´sin) the ground substance that binds together the collagen and elastin fibrils of bone.

osseous
(os´e-әs) of the nature or quality of bone; bony.

osseous cell
a bone cell.

osseous hydatid cysts
hydatid cysts formed by the larvae of Echinococcus granulosus in bone, which may become weakened and eroded by the exuberant growth.

osseous labyrinth
bony labyrinth.

osseous lacuna
bone lacuna.

osseous tissue
the specialized tissue forming the bones.

ossicle
(os´ĭ-kәl) a small bone, especially one of the auditory ossicles in the middle ear. adj., ossic´ular., adj. auditory ossicles the small bones of the middle ear, the incus, malleus, and stapes. Auditory ossicles.

ossicular
(ә-sik´u-lәr) pertaining to an ossicle.

ossiculectomy
(os″ĭ-ku-lek´tә-me) surgical excision of one or more of the ossicles of the middle ear.

ossiculotomy
(os″ĭ-ku-lot´ә-me) incision of the auditory ossicles.

ossiculum
(ә-sik´u-lәm) ossicle.

ossiferous
(ә-sif´әr-әs) producing bone.

ossific
(ә-sif´ik) forming or becoming bone.

ossification
(os″ĭ-fĭ-ka´shәn) formation of or conversion into bone or a bony substance.

ossification center
ossification point any point in bones at which ossification begins.

ossify
(os´ĭ-fi) to change or develop into bone.

ossifying fibroma
ossifying fibroma of bone a benign, relatively slow-growing, central bone tumor, usually of the jaws, especially the mandible, composed of fibrous connective tissue within which bone is formed.

ostealgia
(os″te-al´jә) pain in the bones; called also osteodynia.

ostearthritis
(os″te-ahr-thri´tis) osteoarthritis.

ostearthrotomy
(os″te-ahr-throt´ә-me) excision of an articular end of a bone.

ostectomy
(os-tek´tә-me) excision of a bone or part of a bone.

osteectopia
(os″te-ek-to´pe-ә) displacement of a bone.

ostein
(os´te-in) ossein.

osteitis
(os″te-i´tis) inflammation of bone, often with enlargement, tenderness, and a dull, aching pain.

osteitis deformans
(os″te-i´tis de-for´manz) rarefying osteitis of unknown cause resulting in deformed bones of increased mass leading to bowing of the long bones and deformation of the flat bones. Called also Paget disease of bone. a disease of bone in which the body repeatedly resorbs bone and then tries to repair th...

osteitis fibrosa cystica
(os″te-i´tis fi-bro´sә sis´tĭ-kә) rarefying osteitis with fibrous degeneration and the formation of cysts and the presence of fibrous nodules on the affected bones, due to osteoclastic activity secondary to hyperparathyroidism. If a tumor of the parathyroid gland is the cause of the hyperparathyro...

osteitis fragilitans
(os″te-i´tis frә-jil´ĭ-tanz) osteogenesis imperfecta.

osteitis fungosa
(os″te-i´tis fәng-go´sә) chronic osteitis in which the haversian canals are dilated and filled with granulation tissue.

ostempyesis
(os″tәm-pi-e´sis) suppuration within a bone.

osteoarthritis
(os″te-o-ahr-thri´tis) a noninflammatory degenerative type of arthritis marked by degeneration of the articular cartilage, overgrowth of bone at the margins, and changes in the synovial membrane. Symptoms vary from mild to severe; there may be restriction of movement, but it is usually not as severe as that seen in ...

osteoarthritis deformans
(os″te-o-ahr-thri´tis de-for´manz) osteoarthritis deformans endemica (os″te-o-ahr-thri´tis de-for´manz en-dem´ĭ-kә) Kashin-Bek disease.

osteoarthropathy
(os″te-o-ahr-throp´ә-the) any disease of the joints and bones. hypertrophic pulmonary osteoarthropathy , secondary hypertrophic osteoarthropathy symmetrical osteitis of the four limbs, chiefly localized to the phalanges and terminal epiphyses of the long bones...

osteoarthrosis
(os″te-o-ahr-thro´sis) chronic noninflammatory bone disease.