Medical terms - Letter O (page 2) | MedicalVocabulary.org

Ocular

Having to do with the eye. In a microscope, the lens closest to the eye is termed the ocular (the eyepiece) whereas the objective (also called the objective lens) is the lens nearest to the object being examined. The…
Ocular conjunctiva

That part of the conjunctiva, a clear membrane of the eye, which covers the outer surface of the eye. The other part of the conjunctiva is the palpebral conjunctiva, which lines the inside of the eyelids. The ocular…
Ocular histoplasmosis syndrome

An eye disease that is a leading cause of vision loss, due to the spread of spores of the fungus Histoplasma capsulatum (histo) from the lungs to the eye where they lodge in the choroid (a layer of blood vessels that…
Ocular melanoma

See: Melanoma, ocular
Ocular prosthesis

1. An artificial replacement for an eyeball. In other words, an artificial eye, a globe of glass or plastic colored so it looks like an eyeball. 2. In the strict sense, any artificial aid to vision such as, for example…
Oculo-auriculo-vertebral spectrum

See: Goldenhar syndrome
Oculoauriculovertebral dysplasia

See: Goldenhar syndrome
Oculocraniosomatic syndrome

See: Kearns-Sayre syndrome
Oculocutaneous albinism

See: Albinism, oculocutaneous
Oculodentodigital dysplasia

A genetic disorder that affects many body structures and systems, including the eyes, face, teeth, fingers and toes, and may also cause hearing loss, heart trouble and neurological problems. The disorder is due to…
Oculomotor nerve

The oculomotor nerve is the third cranial nerve. (The cranial nerves emerge from or enter the cranium, the skull, as opposed to the spinal nerves which emerge from the vertebral column). The oculomotor nerve is…
Oculoplastics

Eye plastic and reconstructive surgery., a specialized area of ophthalmology that focuses on the eyelids and the structures surrounding the eye, including problems of the lacrimal (tear) system and the orbit, the region…
OD (lens prescription)

Abbreviation of 'oculus dexter.' Latin for 'right eye.' (The words 'dexterity' and 'dextrous' derive from 'dexter' since the right hand is usually more skillful than the left.) OS stands for 'oculus sinister' which is…
ODD syndrome

Oculodentodigital dysplasia
Odynophagia

Pain on swallowing food and fluids, a symptom often due to disease of the esophagus. From the Greek roots odyno-, pain + -phagia, from phagein, to eat
Oesophagus

Alternate spelling for esophagus. The British have an oesophagus while Americans have an esophagus. But on both sides of the Atlantic it is known as the swallowing tube. Inflammation of this organ is known as…
Off-label use

In the United States, the regulations of the Food and Drug Administration (FDA) permit physicians to prescribe approved medications for other than their intended indications. This practice is known as off-label use
Off-pump

Not on the pump, usually meaning not on the heart-lung machine. See also: Off-pump surgery
Off-pump CABG

A coronary artery bypass graft (CABG) done without putting the patient on the heart-lung machine. Off-pump CABG permits surgery on multiple vessels within the heart by mechanically stabilizing it. Off-pump surgery is…
Off-pump surgery

A technique for heart surgery designed to avoid use of the heart-lung machine. The technique permits surgery on multiple vessels within the heart by mechanically stabilizing it. Off-pump surgery is minimally invasive…
Office of Human Research Protections (OHRP)

The agency responsible for developing, monitoring and exercising compliance over the protections afforded human subjects in all research supported by the US Department of Health and Human Services (DHHS). Formerly…
Offspring

The offspring are strictly speaking the progeny, or young, born to a person. In a larger sense, the offspring are collectively all of the descendants, brood or family. For example, the offspring of someone with a…
OGG1

A DNA repair enzyme with antimutator activity. OGG1 is one of a number of enzymes that repair damage done to DNA by environmental mutagens such as those in cigarette smoke. The gene for OGG1 is located on chromosome…
OHRP

The Office of Human Research Protections, the agency responsible for developing, monitoring and exercising compliance over the protections afforded human subjects in all research supported by the US Department of Health…
Oil, tropical

Coconut, palm kernel or palm oil. Like all fats and oils, these three oils contain various types of fatty acids but, unlike other plant oils, they contain a great deal of saturated fatty acids. Coconut oil is 92%, palm…
Ointment

A medication preparation that is applied topically (onto the skin). An ointment has an oil base whereas a cream is water-soluble. (The word ointment comes from the Latin ungere meaning anoint with oil).
Okihiro syndrome

The association of Duane syndrome (eye retraction) with forearm malformation and deafness. Okihiro syndrome is inherited in an autosomal dominant manner and is due to mutation of a gene located in chromosome region…
OKT3

Brand name for muromonab-CD3, an immunosuppressant drug given intravenously to reverse acute rejection of transplanted organs, including the heart, kidneys and liver. OKT3 was the first monoclonal antibody used to treat…
Olecranon

Of or pertaining to the bony tip of the elbow. The olecranon is, in fact, the near end of the ulna, the bone in the forearm, that forms the pointed portion of the elbow. The triceps muscle tendon of the back of the arm…
Olefaction

Common misspelling of olfaction
Olefactory

Common misspelling of olfactory
Olfaction

The sense of smell, part of the chemical sensing system, or the chemosenses. Sensory cells in the nose, mouth, and throat have a role in helping interpret smells and taste flavors. Microscopic molecules released by…
Olfactory

Pertaining to olfaction, the sense of smell
Olfactory apparatus

The entire system needed to have a sense of smell. This system involves at least 1,000 genes for the olfactory receptors. These genes are members of a large family of genes that encode signaling proteins required for…
Olfactory bulb

A key part of the olfactory apparatus consisting of a bulbous enlargement of the end of the olfactory nerve on the under surface of the frontal lobe of each cerebral hemisphere just above the nasal cavity. Called also…
Olfactory disorder

A loss in the ability to smell or a change in the way odors are perceived. Reduction of the sense of smell is termed hyposmia. Total inability to detect odors is termed anosmia. As for changes in the perception of…
Olfactory nerve

A nerve that registers smells by carrying the impulses for the sense of smell from the nose to the brain. Olfactory nerves continually regenerate -- through all of childhood and adulthood. The olfactory nerves are the…
Olfactory system

See: Olfactory apparatus
Oligo- (prefix)

Means just a few or scanty. From the Greek 'oligos', few, scanty. Examples of terms starting with oligo- include oligodactyly (few fingers), oligohydramnios (too little amniotic fluid) and oligospermia (too few sperm)
Oligoarthritis

Inflammation of four or fewer joints
Oligodactyly

Fewer than the normal number of fingers or toes. Oligo- is from the Greek 'oligos' (few or scanty) + -dactyly from the Greek 'dactylos' (finger) = few fingers. Oligodactyly is the opposite of polydactyly which means too…
Oligodendrocyte

A type of cell in the central nervous system. The oligodendrocytes surround and insulate the long fibers (the axons) through which the nerves send their electrical messages. The term 'oligodendrocyte' comes from the…
Oligodendroglioma

A rare slow-growing type of brain tumor that begins in cells called oligodendrocytes, which provide support and nourishment for cells that transmit nerve impulses. Also called an oligodendroglial tumor.
Oligohydramnios

Scant amniotic fluid: less than usual.
Oligomenorrhea

A reduction in number of menstrual periods and/or amount of menstrual flow.
Oligonucleotide

A small DNA molecule composed of a few nucleotide bases. The term 'oligonucleotide' applies similarly to RNA
Oligonucleotide probe

A short sequence of nucleotides synthesized to match a region where a mutation is known to occur and then used as a molecular probe to detect the mutation
Oligopeptide

A molecule composed of a few amino acids linked to one another. Oligo- means a few
Oligospermia

Fewer sperm than normal. Azoospermia, by contrast, means absolutely no sperm at all.
Oliguria

Less urination than normal.