Medical terms - Letter O (page 5) | MedicalVocabulary.org

Oral cholecystogram

Oral cholecystogram: Abbreviated OCG. An x-ray procedure for diagnosing gallstones. The patient takes iodine-containing tablets by mouth for one night or two nights in a row. The iodine is absorbed from the intestine…
Oral contraceptive

A birth control pill taken by mouth. Most oral contraceptives include both estrogen and progesterone. When given in certain amounts and at certain times in the menstrual cycle, these hormones prevent the ovary from…
Oral contraceptive, combined

Commonly called 'the pill,' combined oral contraceptives are the most commonly used form of reversible birth control in the United States. This form of birth control suppresses ovulation (the monthly release of an egg…
Oral glucose tolerance test

A test to determine the body's ability to handle glucose . In the test, a person fasts overnight (at least 8 but not more than 16 hours). Then first, the fasting plasma glucose is tested. After this test, the person…
Oral moniliasis

Yeast infection of the mouth and throat caused by a fungus formerly called Monilia, now known as Candida albicans. This infection is also known as thrush. Yeast organisms are part of the germs normally found in various…
Oral rehydration salts

ORS. A solution of glucose-based salt solution used in oral rehydration therapy. WHO and UNICEF recommend a single formulation of glucose-based ORS to treat or prevent dehydration from diarrhea from any cause, including…
Oral rehydration therapy

The administration of special fluids by mouth treat dehydration. Abbreviated ORT. See also: Oral rehydration salts
Oral surgeon

A dentist with special training in surgery of the mouth and jaw.
Oral-motor

Relating to the muscles of the mouth and/or mouth movements
Orbit

In medicine, the bony cavity in which the eyeball sits together with its associated muscles, blood vessels, and nerves. The orbit is formed of parts of the ethmoid, frontal, lacrimal, nasal, palatine, sphenoid, and…
Orbital

Relating to the orbit, in anatomy the bony cavity that contains the eyeball
Orbital fracture

A break in one of the bones that make up the orbit. Since the orbit is the seat of the globe (the eye), an orbital fracture can be a serious, sight-threatening break. (Goggles are recommended for racquetball and…
Orbital ridge

The bony ridge beneath the eyebrow
Orchiectomy

The surgical removal of one or both testes.
Orchiopexy

Surgery to bring down an undescended testicle
Orchitis

Inflammation of the testis (male sex organ). There are many causes of inflammation of the testis including infections (such as mumps), diseases (such as polyarteritis nodosa), or injury. Also called orchiditis
Ordre des Medecins

The Conseil National de l'Ordre des Médecins. The French equivalent of the American Medical Association (the AMA)
Ordre des Medecins

The Conseil National de l'Ordre des Médecins. The French equivalent of the American Medical Association (the AMA)
ORF

Open reading frame
Organ

A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver
Organ failure

The failure of an essential system in the body. Multiple organ failure is the failure of two or more systems, such as the cardiovascular, and renal systems, and is a common consequence of sepsis (the presence of…
Organ of hearing

See: Cochlea
Organic

1. A chemical compound that contains carbon.2. Related to an organ.3. Grown or prepared without the use of chemicals or pesticides, as in organic food
Organic brain syndrome

Psychiatric or neurological symptoms, including problems with attention, concentration, and memory, confusion, anxiety, and depression, arising from damage to or disease in the brain. Also called organic mental…
Organic dust toxic syndrome

A flu-like illness due to the inhalation of grain dust with symptoms including fever, chest tightness, cough and muscle aching. The inhalation of the grain dust may occur in an agricultural setting or from covering a…
Organisation Mondiale de la Sante

The French name for the World Health Organization (WHO). See: World Health Organization
Organotherapy

The use of extracts of animal glands or organs to treat disease. Pituitary extracts from pigs, for example, were used for many years to treat hormone disorders
Organs of reproduction, female

The internal genital structures of the female include the ovaries, the Fallopian tubes, the uterus (womb) and the vagina. The ovaries or 'egg sacs' are a pair of female reproductive organs located in the pelvis, one on…
Organs of reproduction, male

>The male external genitalia -- the penis, the male urethra, and the scrotum; and >The male internal genitalia -- the testis, epididymis, ductus deferens, seminal vesicle, ejaculatory duct, bulbourethral gland, and the…
Orgasm

The climax of coitus, consisting of a series of involuntary muscle contractions in the anus, lower pelvic muscles, and sexual organs, accompanied by a sudden release of endorphins providing a feeling of euphoria. In the…
Orgasmic disorder

See: Anorgasmia.
Orgasmic dysfunction

See: Anorgasmia
Orgasmic inhibition

See: Anorgasmia
Oriental lung fluke

Paragonimus westermani. See: Paragonimiasis
Oriental medicine (traditional)

His is a sophisticated form of medicine that is comprised of many systematic techniques and methods, including acupuncture, herbal medicine, acupressure, qi gong, and oriental massage. The most striking characteristic…
Orientation, anatomic terms of

See Anatomic terms of orientation
Orifice

An opening. The mouth for example is an orifice.
Ornithine

An amino acid that is not found in protein but is important in the formation of urea and the disposal of excess nitrogen. Ornithine is produced when urea is split off from arginine and ornithine is itself converted into…
Ornithine transcarbamylase (OTC) deficiency

A rare metabolic disorder, OTC is one of the urea-cycle disorders. The urea cycle is a series of five liver enzymes that help rid the body of ammonia, a toxic breakdown product of protein. When one of these enzymes is…
Ornithophobia

An abnormal and persistent fear of birds. Sufferers from ornithophobia experience undue anxiety about encountering and even being attacked by birds although they may realize their fears are quite irrational…
Oromandibular dystonia

Oro- refers to the mouth and mandibular refers to the lower jaw. Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. The jaw may be pulled either open or shut, and speech and swallowing can be…
Oropharynx

The area of the throat that is at the back of the mouth. The oropharynx is in contrast to the nasopharynx, the part of the throat that lies behind the nose
Orphan disease

A disease which has not been 'adopted' by the pharmaceutical industry because it provides little financial incentive for the private sector to make and market new medications to treat or prevent it. An orphan disease…
Orphan drug

1. Oral rehydration salts. 2. Oral rehydration solution. 3. Orthopaedic Research Society.
ORS

1. Oral rehydration salts. 2. Oral rehydration solution. 3. Orthopaedic Research Society
Ortho- (prefix)

Prefix meaning straight or erect. From the Greek 'orthos' that means just that: straight or erect. Examples of terms involving ortho- include orthodontics (straightening the teeth), orthopaedics (straightening the…
Orthodontic treatment (dental braces)

Dental braces: The use of devices to move teeth or adjust underlying bone. The ideal age for starting orthodontic treatment is between ages 3 to 12 years. Temporomandibular joint (TMJ) problems can be corrected with…
Orthodontics

Orthodontics is the branch of dentistry that specializes in the diagnosis, prevention and treatment of dental and facial irregularities. The technical term for these problems is 'malocclusion,' which means 'bad bite.'…
Ortholog

A gene in two or more species that has evolved from a common ancestor. Also called an orthologous gene
Orthologous gene

1. A term coined by the chemist Linus Pauling who defined it as "the preservation of good health and the treatment of disease by varying the concentration in the human body of substances that are normally present in the…