Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «R»:
Roentgen: An international unit of X-radiation or
gamma-radiation. Abbreviated R. Named for Wilhelm Roentgen....
Roentgen ray: Term coined around 1890 that preceded X-ray and is now synonymous with it. Named for Wilhelm Roentgen, a German professor of physics. Roentgen wanted to prove his hypothesis that cathode rays could penetrate substances besides air. When he saw that he could film his
thumb and forefing...
Roentgen, Wilhelm: Wilhelm Conrad Rontgen
(1845-1923), German-born, Dutch-educated physicist who first observed and documented X-rays on November 8, 1895. He made this seminal discovery by accident while experimenting with a set of cathode ray instruments. He was surprised to find a flickering imag...
Roentgenology: Radiology, the science of
radiation and, specifically, the use of both ionizing (like X-ray) and nonionizing (like
ultrasound) modalities for the diagnosis and treatment of disease.
Roentgenology is named
for Wilhelm Conrad Roentgen who discovered X-rays. Roentgen, a professor of ...
Rohypnol: The trade name for flunitrazepam, which has been abused as a "date rape" drug. Rohypnol produces sedative-hypnotic effects including muscle relaxation and amnesia. It can produces physical and psychological dependence and can be lethal when mixed with alcohol and/or other depressants. It i...
ROMA: Representational oligonucleotide microarray analysis. A method for the detection of genomic aberrations between any two samples of DNA. ROMA measures the relative concentration of DNA in the two samples by hybridizing differentially labeled samples to a set of probes. By arraying oligonucleot...
Romano-Ward syndrome: See: Long QT syndrome....
Roofer's knee: See prepatellar bursitis. ...
Roofies: Street term for Rohypnol....
Rooting reflex: A reflex seen in newborn babies, who
automatically turn their face toward the stimulus and make sucking
(rooting) motions with the mouth when the cheek or lip is touched.
The rooting reflex helps to ensure breastfeeding....
Rorschach test: A psychological test involving inkblots. The inkblots are used to determine what a person perceives (reads into) in the enigmatic and highly ambiguous shapes. Ten standardized blots are shown one at a time to a subject and their responses are recorded. The Rorschach test became a co...
Rosacea: A chronic skin disease that affects the middle third of the face with persistent redness over the areas of the face and nose that normally blush: mainly the forehead, the chin and the lower half of the nose. The tiny blood vessels in these areas enlarge (dilate) and become more visible thr...
Rosacea keratitis: A condition affecting the eyes in about half of all cases of rosacea. It is characterized by burning and
grittiness of the eyes (conjunctivitis). If this is not treated,
inflammation of the cornea may impair vision....
Rosary pea: See: Abrin....
Roseola is a childhood illness caused by virus infection characterized by high fevers followed by a skin rash.
Roseola is also formally called roseola infantum or roseola infantilis.
The following is a brief summary of roseola:
Cause: Roseola is caused by a virus called human herpesvirus 6 ...