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

right superior pulmonary vein
a vein that returns blood from the upper and middle lobes of the right lung (from the middle lobe, apical, anterior segmental, and posterior segmental veins) to the left atrium of the heart.

right suprarenal vein
a vein that drains the right suprarenal gland into the inferior vena cava.

right testicular vein
a vein that drains the right pampiniform plexus and empties into the inferior vena cava.

right ventricle of heart
the lower chamber of the right side of the heart, which pumps venous blood through the pulmonary trunk and arteries to the capillaries of the lung.

right ventricular failure
right ventricular heart failure see right ventricular heart failure.

right-sided heart failure
right ventricular heart failure failure of proper functioning of the right ventricle, with subsequent engorgement of the systemic veins, producing pitting edema, enlargement of the liver, and ascites. Called also right ventricular failure.

right-to-left shunt
diversion of blood from the right side of the heart to the left side or from the pulmonary to the systemic circulation through an anomalous opening such as septal defect or patent ductus arteriosus.

righting reactions
(rīt´ing) responses of the head and eyes that occur as the body processes sensory input from the visual and vestibular systems. Their purpose is to maintain the correct orientation of the head and body with respect to the vertical.

righting reflex
the ability to assume an optimal position when there has been a departure from it.

rigid contact lens
hard contact lens.

rigidity
(rĭ-jid´ĭ-te) inflexibility or stiffness. paratonic rigidity an intermittent abnormal increase in resistance to passive movement in a comatose patient.

rigor
(rig´or) (ri´gor) strict discipline or scrupulous adherence to a given set of standards. rigidity. chill. rigor mortis the stiffening of a dead body accompanying depletion of adenosine triphosphate in the muscle fibers.

Riley-Day syndrome
(ri´le da´) familial dysautonomia. an autosomal recessive disease of childhood characterized by defective tear formation, skin blotching, emotional instability, motor incoordination, total absence of pain sensation, and hyporeflexia; seen almost exclusively in Ashkenazi Jews. Called also familial dys...

Riley-Smith syndrome
(ri´le smith´) macrocephaly without hydrocephalus, multiple hemangiomas, and pseudopapilledema; presumed to be transmitted as an autosomal dominant trait.

riluzole
(ril´u-zōl) a compound used to prolong survival time in the treatment of amyotrophic lateral sclerosis.

rim sign
cortical rim sign.

rima
(ri´mә) Latin word meaning cleft or crack. rima glottidis the elongated opening between the true vocal cords and between the arytenoid cartilages; called also vocal area. Rima glottidis in coronal section showing posterior view of a...

rimantadine
(ri-man´tә-dēn) an antiviral agent used in prophylaxis and treatment of influenza A.

rimexolone
(rĭ-mek´sә-lōn″) a corticosteroid used in topical treatment of inflammation following eye surgery and of uveitis affecting the anterior structures of the eye.

rimula
(rim´u-lә) a minute fissure, as of the spinal cord or brain.

ring
(ring) any annular or circular organ, structure, or area. in chemistry, a collection of atoms united in a continuous or closed chain.

ring abscess
a ring-shaped purulent infiltration at the periphery of the cornea.

ring chromosome
(r) a chromosome in which both ends have been lost (deletion) and the two broken ends have reunited to form a ring.

ring scotoma
annular scotoma.

ring test
(for antibiotic activity) the solution is placed in a ring resting on the surface of seeded agar and the size of the surrounding clear area of inhibition indicates the activity.

ring ulcer
in a corneal ulcer, fusion of foci of ulceration to form a peripheral ring.

Ringer solution
(ring´er) a sterile solution of sodium chloride, potassium chloride, and calcium chloride in purified water, used as a fluid and electrolyte replenisher and an irrigating physiologic salt solution. A preparation for injection is known as Ringer's injection, and one for irrigation as Ringer's irrigation. Lactated Ringer'...

ringform congenital cataract
a very rare opacity in which the nucleus of the lens is absent, and only a doughnut-shaped remnant of lens is left.

ringworm
(ring´wәrm) the popular name for tinea, a fungal infection of the skin, even though it is not caused by a worm and is not always ring-shaped. It is caused by a group of related fungi that feed on the body's waste products of dead skin and perspiration; they attack the skin in various areas, especially body f...

Rinne test
(rin´ә) a tuning fork test that compares the duration of perception by bone conduction and by air conduction. In the normal ear, the fork is heard twice as long by air conduction as by bone conduction.

Riolan bones
(re″o-lah´) small bones sometimes found in the suture between the occipital bone and the petrous part of the temporal bone.

Riopan
(ri´o-pan) trademark for preparations of magaldrate, either alone or in combination with simethicone, used as low-sodium antacids.

ripe cataract
mature cataract.

risedronate
(ris-ed´ro-naāt″) an inhibitor of bone resorption used as the sodium salt in the treatment of osteitis deformans and for the prevention and treatment of osteoporosis, administered orally.

risk
(risk) a danger or hazard; the probability of suffering harm. See also risk factor. attributable risk the amount or proportion of incidence of disease or death (or risk of disease or death) in individuals exposed to a specific risk factor that can be attributed to exposure to tha...

risk factor
an agent or situation that is known to carry a risk, making an individual or population more susceptible to the development of a specific negative condition.

risk ratio
relative risk.

risorius muscle
origin, fascia over masseter muscle; insertion, skin at corner of mouth; innervation, buccal branch of facial nerve; action, pulls corner of mouth laterally.

risperidone
(ris-per´ĭ-dōn) an orally administered antipsychotic agent; its mechanism of action is unknown, but it may function as an antagonist to dopamine and serotonin.

RIST
radioimmunosorbent test.

risus
(ri´sәs) Latin word meaning laughter. risus sardonicus a grinning expression produced by spasm of the facial muscles; seen in tetanus and certain types of poisoning.

Ritalin
(rit´ә-lin) trademark for preparations of methylphenidate hydrochloride, a mild central nervous system stimulant.

ritodrine
(rit´oh-drēn) a β2-adrenergic receptor agonist used in the form of the hydrochloride salt as a smooth muscle (uterine muscle) relaxant to decrease uterine activity and delay uncomplicated premature labor.

ritonavir
(ri-to´nә-vir) an HIV protease inhibitor that causes the human immunodeficiency virus to form noninfectious particles; used to treat HIV infection and AIDS, administered orally.

Ritter disease
(rit´әr) dermatitis exfoliativa neonatorum.

rituximab
(rĭ-tuk´sĭ-mab) a monoclonal antibody that binds CD20 antigen; used as an antineoplastic agent in treatment of B-cell non-Hodgkin lymphoma positive for that antigen, administered intravenously.

rivalry
(ri´vәl-re) a state of competition or antagonism. sibling rivalry competition between siblings for the love, affection, and attention of one or both parents or for other recognition or gain.

rivastigmine
(riv″ә-stig´mēn) a reversible inhibitor of cholinesterase, believed to increase the level of acetylcholine available in the central nervous system; administered orally as the tartrate salt as an adjunct in the treatment of mild to moderate dementia of the Alzheimer type.

Rivinus notch
tympanic notch.

rizatriptan
(ri″zә-trip´tan) a selective serotonin receptor agonist used as the benzoate salt in the acute treatment of migraine.

riziform
(riz´ĭ-form) resembling grains of rice.

RLL
right lower lobe (of lung).

RLQ
right lower quadrant (of abdomen).

RMA
right mentoanterior (position/presentation of the fetus). See presentation.

RMP
right mentoposterior (position/presentation of the fetus). See presentation.

RMT
right mentotransverse (position/presentation of the fetus). See presentation.

RN
Registered Nurse.

Rn
radon.

RNA
ribonucleic acid: a nucleic acid that is present in all living cells and controls cellular protein synthesis, playing several roles in the flow of genetic information from deoxyribonucleic acid (DNA) to proteins. It is quite similar to DNA in composition, and it replaces DNA as the carrier of the genetic code in some viruses.

RNA virus
a virus whose genome consists of RNA.

RNA-directed DNA polymerase
(dĭ-rek´tәd pә-lim´әr-ās) reverse transcriptase.

RNase
ribonuclease.

RNP
ribonucleoprotein.

ROA
right occipitoanterior (position/presentation of the fetus). See presentation.

Robaxin
(ro-bak´sin) trademark for preparations of methocarbamol, a skeletal muscle relaxant.

Robert ligament
(ro-bār´) posterior meniscofemoral ligament.

Roberts syndrome
(rob´әrts) a hereditary syndrome, transmitted as an autosomal recessive trait, consisting of imperfect development of the long bones of the limbs associated with cleft palate and lip and other anomalies.

Robertson sign
fibrillary contraction of the pectoralis muscle over the cardiac area in approaching death from heart disease. absence of pupillary dilatation on pressure over alleged painful areas in malingering. in ascites, fullness and tension in the patient's flanks, felt by the examiner with the patient supine.

Robin syndrome
(ro-bă´) Pierre Robin syndrome.

Robinow syndrome
(rob´ĭ-nou) dwarfism associated with increased interorbital distance, malaligned teeth, bulging forehead, depressed nasal bridge, and short limbs. Called also Robinow dwarfism and fetal face syndrome.

Robinson catheter
a straight urethral catheter with two to six openings to allow drainage, especially useful in the presence of blood clots which may occlude one or more openings.

Robson position
a position for surgery of the biliary tract; the patient lies supine with a sandbag beneath the eleventh and twelfth ribs.

Rocaltrol
(ro´kal-trōl) trademark for preparations of calcitriol, a form of vitamin D.

Rocephin
(ro-sef´in) trademark for a preparation of ceftriaxone sodium, a cephalosporin antibiotic.

Rochalimaea
(ro″kә-li-me´ә) a former genus of bacteria that is now merged with Bartonella.

Rochon-Duvigneaud syndrome
(ro-shaw´doo-ve-nyo´) superior orbital fissure syndrome.

Rocio virus
a mosquito-borne virus of the genus Flavivirus occurring in Brazil that causes a sometimes fatal encephalitis.

Rockey-Davis incision
an incision similar to the McBurney incision, except that the skin incision is transverse rather than vertical.

Rocky Mountain spotted fever
(rok´e moun´tәn) an infectious tick fever originally seen in the Rocky Mountains of North America but now recognized in other parts of the Americas. It belongs to a group of insect-borne fevers caused by microscopic parasites known as rickettsiae, which attack the cells lining small blood vessels. The species Rick...

rocuronium
(ro″ku-ro´ne-әm) a neuromuscular blocking agent, used as the bromide salt as an adjunct in general anesthesia to facilitate endotracheal intubation and as a skeletal muscle relaxant during surgery or mechanical ventilation; administered intravenously.

rod
(rod) a straight, slim mass of substance. one of two types of visual cells in the retina; rods are cylindrical in shape and contain rhodopsin. Together with the cones they form the light-sensitive elements of the eye. See also eye and vision. Called also retinal rod. Corti rods ...

rod cells
retinal rods. microglia as observed in chronic diseases of the cerebral cortex and in dementia paralytica, in which the cells are markedly attenuated in form, their processes being confined mainly to the two extremities. littoral cells.

rod granules
the nuclei of the visual cells in the outer nuclear layer of the retina; they are connected with the rods.

rodent ulcer
ulcerating basal cell carcinoma.

rodenticide
(ro-den´tĭ-sīd) destructive to rodents. an agent with this effect.

rodenticide poisoning
poisoning by the effects of rodenticides; in humans it is rarely accidental but may occur in cases such as suicide attempts. Domestic animals may sicken and even die after either eating the poison directly or consuming rodents that have died from the poison. Poisoning by anticoagulant rodenticides such as indanedione and ...

roentgen rays
x-rays.

roentgenograph
(rent´gәn-o-graf) radiograph.

roentgenography
(rent″gәn-og´rә-fe) radiography. adj., roentgenograph´ic., adj.

roentgenologist
(rent″gәn-ol´ә-jist) radiologist.

roentgenology
(rent″gәn-ol´ә-je) radiology.

roentgenoscope
(rent-gen´o-skōp) fluoroscope.

roentgenoscopy
(roentgen rays) (rent″gәn-os´kә-pe) fluoroscopy.

rofecoxib
(ro″fә-cok´sib) a nonsteroidal antiinflammatory drug of the cox-2 inhibitors group, used in treatment of osteoarthritis, acute pain, and dysmenorrhea.

Roger disease
(ro-zha´) a ventricular septal defect; the term is usually restricted to small, asymptomatic defects.

Roger reflex
esophagosalivary reflex.

Rohon-Beard cells
giant ganglion cells in the spinal cord of some vertebrates.

Rokitansky hernia
protrusion of a sac of mucous membrane or of the peritoneum through separated muscular fibers of the intestine.

Rokitansky-Cushing ulcer
Cushing ulcer.

Rokitansky-Küster-Hauser syndrome
(ro″kĭ-tahn´ske ke´stәr hou´zer) Mayer-Rokitansky-Küster-Hauser syndrome.