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

retraction ring
a circular thickening and indentation that goes around the uterus during labor, at the junction of the isthmus and corpus uteri. Normally, as contractions progress during labor the upper segment of the uterus becomes thicker and more active while the lower dilating segment becomes thin-walled, supple, and passive. The bou...

retraction syndrome
Duane syndrome.

retractor
(re-trak´tәr) an instrument for holding open the edges of a wound or drawing back structures. a muscle that draws a part back.

retrieval
(re-tre´vәl) in psychology, the process of obtaining memory information from wherever it has been stored.

retroaction
(ret″ro-ak´shәn) action in a reversed direction; see also reaction.

retroauricular
(ret″ro-aw-rik´u-lәr) behind the auricle of the ear.

retrobulbar
(ret″ro-bul´bәr) behind the pons. behind the eyeball.

retrobulbar block
that performed by injection of a local anesthetic into the retrobulbar space to anesthetize and immobilize the eye.

retrobulbar neuritis
retrobulbar optic neuritis optic neuritis affecting the part of the optic nerve behind the eyeball.

retrobulbar pupillary reflex
slight dilation of the pupil, which contracts under light stimulation and then dilates while the light stimulation is still present.

retrocalcaneal bursitis
achillodynia.

retrocervical
(ret″ro-sur´vĭ-kәl) behind the cervix uteri.

retrocession
(ret″ro-sesh´әn) a going backward; backward displacement.

retrocochlear
(ret″ro-kok´le-әr) behind the cochlea. denoting the eighth cranial nerve and cerebellopontine angle, as opposed to the cochlea.

retrocochlear hearing loss
sensorineural hearing loss in which the lesion is proximal to the cochlea, in the vestibulocochlear nerve or one of the auditory areas of the brain.

retrocollic
(ret″ro-kol´ik) nuchal. pertaining to torticollis.

retrocollis
(ret″ro-kol´is) spasmodic torticollis in which the head is drawn back.

retrocursive
(ret″ro-kur´siv) marked by stepping backward.

retrodeviation
(ret″ro-de″ve-a´shәn) any displacement backwards; the term includes retroversion, retroflexion, and other deviations. Called alsoretrodisplacement and retroposition.

retrodisplacement
(ret″ro-dis-plās´mәnt) retrodeviation.

retroduodenal arteries
origin, first branch of gastroduodenal artery; branches, none; distribution, bile duct, duodenum, head of pancreas.

retrofilling
(ret″ro-fil´ing) a method of root canal therapy in which the canal is filled from the apex, which has been surgically exposed.

retrofitting
(ret´ro-fit″ing) the architectural modification of a building to meet current standards, particularly regarding access for the handicapped.

retroflexion
(ret″ro-flek´shәn) the bending of an organ or part so that its top is thrust backward, such as bending backward of the body of the uterus upon the cervix. Retroflexion of uterus.

retrogasserian
(ret″ro-gә-sēr´e-әn) pertaining to the sensory (posterior) root of the trigeminal (gasserian) ganglion.

retrognathia
(ret″ro-nath´e-ә) retrognathism.

retrognathism
(ret″ro-nath´iz-әm) retrusion of the mandible. Called also retrognathia. adj., retrognath´ic., adj.

retrograde
(ret´ro-grād) moving backward or against the usual direction of flow. degenerating, deteriorating, or catabolic.

retrograde amnesia
inability to recall events that occurred prior to the episode precipitating the disorder. Unlike anterograde amnesia, it is the loss of memories of past events.

retrograde conduction
transmission of a cardiac impulse backward in the ventricular to atrial direction; particularly, conduction from the atrioventricular node into the atria.

retrograde extrasystole
a premature ventricular contraction followed by a premature atrial contraction, due to transmission of the stimulus backward, usually over the bundle of His.

retrograde hernia
herniation of two loops of intestine, with the part between them lying inside the abdominal cavity. Called also w hernia.

retrogression
(ret″ro-gresh´әn) degeneration; deterioration; regression; return to an earlier, less complex condition.

retrolental
(ret″ro-len´tәl) behind the lens of the eye.

retromandibular tender point
a point behind the superior extremity of the inferior maxilla below the lobule of the ear and in front of the mastoid process. Pressure on this point elicits extreme pain in meningitis.

retromandibular vein
the vein that is formed in the upper part of the parotid gland behind the neck of the mandible by union of the maxillary and superficial temporal veins; it passes downward through the gland, communicates with the facial vein, and emerging from the gland joins with the posterior auricular vein to form the external jugular ...

retromorphosis
(ret″ro-mor-fo´sis) retrograde metamorphosis.

retroparotid
(ret″ro-pә-rot´id) behind a parotid gland.

retroperitoneal
(ret″ro-per″ĭ-to-ne´әl) behind the peritoneum.

retroperitoneal fibrosis
deposition of fibrous tissue in the retroperitoneal space, producing vague abdominal discomfort and often blockage of the ureters, with resultant hydronephrosis and impaired renal function, which may result in renal failure. Called also Ormond disease.

retroperitoneal hernia
Treitz hernia.

retroperitoneal space
the space between the peritoneum and the posterior abdominal wall; called also retroperitoneum.

retroperitoneum
(ret″ro-per″ĭ-to-ne´әm) retroperitoneal space.

retroperitonitis
(ret″ro-per″ĭ-to-ni´tis) inflammation in the retroperitoneal space.

retropharyngeal space
the space behind the pharynx, containing areolar tissue.

retropharyngitis
(ret″ro-far″in-ji´tis) inflammation of posterior part of the pharynx.

retroplasia
(ret″ro-pla´zhә) retrograde metaplasia; degeneration of a tissue or cell into a more primitive type.

retroposed
(ret´ro-pōzd″) displaced backward.

retroposition
(ret″ro-pә-zish´әn) retrodeviation.

retropubic
(ret″ro-pu´bik) posterior to the pubic arch.

retropubic space
the areolar space bounded by the reflection of peritoneum, symphysis pubis, and bladder.

retropulsion
(ret″ro-pul´shәn) a driving back, as of the fetal head in labor. tendency to walk backward, as in some cases of tabes dorsalis. an abnormal gait in which the body is bent backward.

retrospective study
one in which the subjects are classified as either having some outcome (cases) or lacking it (controls). Cases and controls are often matched with respect to certain demographic or other variables but need not be.

retrosternal
(ret″ro-stur´nәl) behind the sternum.

retrosternal hernia
Bochdalek hernia.

retrovascular hernia
a femoral hernia that passes within the femoral sheath but exits posterior to the femoral vessels.

retroversion
(ret″ro-vur´zhәn) the tipping backward of an entire organ or part, as of the uterus. Retroversion of uterus.

retrovesical
(ret″ro-ves´ĭ-kәl) behind the urinary bladder.

Retrovir
(ret´ro-vir) trademark for preparations of zidovudine, an antiretroviral active against the human immunodeficiency virus.

Retroviridae
(ret″ro-vir´ĭ-de) the retroviruses, a large family of RNA viruses that carry reverse transcriptase. Genera that infect humans include Lentivirus and BLV-HTLV retroviruses.

retrovirus
(ret´ro-vi″rәs) any virus of the family Retroviridae. BLV-HTLV retroviruses a genus of the family Retroviridae; species that infect humans are human T-lymphotropic viruses 1 and 2. human endogenous retroviruses(HERV) retrovirus...

retrusion
(re-troo´zhәn) the state of being located posterior to the normal position, such as the mandible or a tooth displaced in the line of occlusion.

Rett syndrome
(ret) a pervasive developmental disorder affecting the gray matter of the brain, occurring exclusively in females and present from birth; it is characterized by autistic behavior, ataxia, dementia, seizures, and loss of purposeful use of the hands, with cerebral atrophy, mild hyperammonemia, and decreased levels o...

return
(re-tәrn´) a coming back. venous return the flow of blood into the heart from the peripheral vessels.

Retzius space
retropubic s. perilymphatic s.

reuptake
(re-up´tāk) reabsorption of a previously secreted substance.

Reuss test
(for atropine) the substance examined is treated with sulfuric acid and oxidizing agents; if atropine is present, an odor of roses and orange-flowers is given off.

revascularization
(re-vas″ku-lәr-ĭ-za´shәn) the restoration of blood supply, as after a wound. the restoration of an adequate blood supply to a part by means of a blood vessel graft, as in aortocoronary bypass.

Reverdin needle
a surgical needle with an eye that can be opened and closed by means of a slide.

reversal
(re-vur´sәl) a turning or change in the opposite direction. sex reversal a change in characteristics from those typical of one sex to those typical of the other. vasectomy reversal surgical restoration of connection between ducts or vessels in a man w...

reverse mutation
see reversion (def. 2).

reverse transcriptase
(re-vurs´ tran-skrip´tās) an enzyme of RNA viruses that catalyzes the transcription of RNA to DNA, which is then incorporated into the genome of the host cell. This is the reverse of the usual mechanism for replication of genetic information; in the presence of this enzyme it is the RNA that serves as the template ...

reverse transcriptase inhibitor
a substance that blocks activity of the reverse transcriptase of a retrovirus and is used as an antiretroviral agent. Some are nucleosides or nucleoside analogues, and those that are not are therefore often called non-nucleoside reverse transcriptase inhibitors.

reverse Trendelenburg position
a supine position with the patient on a plane inclined with the head higher than the rest of the body and appropriate safety devices such as a footboard.

reverse Waters position
a mento-occipital radiographic position used to demonstrate the facial bones when the patient cannot be placed in a prone position; helpful in demonstrating fractures of the orbits, maxillary sinuses, zygomatic bones, and zygomatic arches.

reversed pupillary reflex
any abnormal pupillary reflex that is opposite to what occurs normally, such as when stimulation of the retina by light dilates the pupil. Called also paradoxical pupillary reflex.

reversed shunt
right-to-left shunt.

reversed three sign
a pair of indentations, one on either side of the aortic knuckle, seen on barium contrast imaging of the esophagus and representing mirror images of a figure three sign; it signifies coarctation of the aorta. Called also E sign.

reversion
(re-vur´zhәn) regression (def. 1). in genetics, the mutation of a mutant phenotype so that the original function is restored, as by mutation of the DNA back to the parental base sequence (reverse mutation) or by suppression.

review
(re-vu´) an assessment or appraisal. peer review a basic component of a quality assurance program in which the results of health care given to patients are evaluated according to outcome criteria established by peers of the professionals delivering the care. eva...

Revilliod sign
orbicularis sign.

revulsion
(re-vul´shәn) the drawing of blood from one part to another, as occurs in counterirritation.

Rexed laminae
an architectural scheme used to classify the structure of the spinal cord, based on the features of the neurons in different regions of the gray substance. It consists of nine laminae (layers), designated by the roman numerals I–IX, that extend throughout the cord, roughly paralleling the dorsal and ventral columns ...

Reye syndrome
(ri) an acute, potentially fatal disease of childhood, characterized by severe cerebral edema and increased intracranial pressure, hypoglycemia, and fatty infiltration and dysfunction of the liver. The cause is unknown, but it is almost always associated with a previous viral infection. Within several hours to a few day...

RFA
right frontoanterior (position/presentation of the fetus). See presentation.

RfD
reference dose.

RFLP
restriction fragment length polymorphism.

RFP
right frontoposterior (position/presentation of the fetus). See presentation.

RFT
right frontotransverse (position/presentation of the fetus). See presentation.

Rh
rhodium. symbol for Rhesus factor (see Rh factor).

Rh antibodies
those directed against the antigen (Rh factor) of human erythrocytes. Not normally present, they may be produced when Rh-negative persons receive Rh-positive blood by transfusion or when an Rh-negative person is pregnant with an Rh-positive fetus.

Rh factor
any of numerous genetically determined antigens (agglutinogens) found on the surface of erythrocytes; there are at least eight different ones. If one of the factors is present in an individual's erythrocytes, the blood type is called Rh positive (D positive, Rh0); if the factor is absent, the blood type is called Rh negative (D negat...

Rh hemolytic disease
a hemolytic reaction in the blood of a fetus or newborn to anti-Rh antibodies in the mother's blood, such as occurs in erythroblastosis fetalis.

Rh-null syndrome
chronic hemolytic anemia affecting individuals who lack all Rh factors (Rhnull); it is marked by spherocytosis, stomatocytosis, and increased osmotic fragility.

Rh0
(D) immune globulin a specific immune globulin derived from human blood plasma containing antibody to the erythrocyte factor Rh0(D); used to prevent Rh-sensitization of Rh-negative females and thus prevent erythroblastosis fetalis in subsequent pregnancies; administered within 72 hours after exposure to Rh-positive blood resulting fro...

rhabditic dermatitis
a type of dermatitis found in domestic animals and occasionally spread to humans, due to invasion of a break in the skin by larvae of the nematode Rhabditis strongyloides, often as a result of sleeping in a damp, filthy bed. Called also Pelodera dermatitis.

Rhabditis
(rab-di´tis) a genus of minute nematodes found mostly in damp earth, and as an accidental parasite in humans.

rhabdoid
(rab´doid) resembling a rod; rod-shaped.

rhabdoid tumor of the kidney
a malignant kidney tumor similar to Wilms tumor but with a poorer prognosis; it has large cells with large nuclei and eosinophilic fibrils in the cytoplasm. It often metastasizes to the brain.

rhabdomyoblast
(rab″do-mi´o-blast″) [rhabdo- + myoblast] the prototypic cell of rhabdomyosarcoma, containing an eccentric nucleus, eosinophilic cytoplasm, and sometimes cross striations resembling those of striated muscle; it may be round, spindle-shaped, or racquet-shaped (strap or tadpole cell).