Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «S»:
Spondylolysis:The breaking down (dissolution) of a portion
of a bony building block of the spine (a vertebra).
The portion of the vertebra that is affected in spondylolysis is a
bone segment called the pars interarticularis (which is part of a
plate which is located, in technical terms, between t...
Spondylosis: Degeneration of the disc spaces between the vertebrae. This finding in the spine is commonly associated with osteoarthritis....
Sponge, vaginal contraceptive
Sponge, vaginal contraceptive: See: Vaginal contraceptive sponge....
Spongiform: Resembling a sponge in being soft and full of cavities, as in as in transmissible spongiform encephalopathy....
Spongiform encephalopathy and cerebral amyloidosis
Spongiform encephalopathy & cerebral amyloidosis: See: Gerstmann-Straussler-Scheinker syndrome....
Spongy degeneration of the central nervous system
Spongy degeneration of the central nervous system: Also called Canavan disease, this is a severe progressive fatal inherited (genetic) disorder of the central nervous system (CNS).
The signs of Canavan disease usually appear when the children are between 3 and 6 months of age. They include developm...
Spontaneous abortion: A miscarriage, that is, any pregnancy
that is not viable (the fetus cannot survive) or in which the fetus is born before the 20th week of pregnancy. Spontaneous
abortion occurs in at least 15-20% of all recognized
pregnancies and usually takes place before the 13th week of
Sporadic: Occurring upon occasion or in a scattered,
isolated or seemingly random way.
A disorder that is sporadic is by definition neither an endemic,
an epidemic, nor a pandemic:
An endemic is present in a community at all
times but in low frequency. An endemic is continuous, as in
the case ...
Sporadic primary pulmonary hypertension
Sporadic primary pulmonary hypertension: See: Pulmonary hypertension....
Sporotrichosis: An infection most commonly of the skin
caused by the fungus Sporothrix schenckii.
Persons handling thorny plants, sphagnum moss, or baled hay are at
increased risk of developing sporotrichosis. Outbreaks of
sporotrichosis have occurred among nursery workers handling sphagnum
Spot, blind: In ophthalmology, a blind spot is:
A small area of the retina where the optic nerve enters the eye; this type of blind spot occurs normally in all eyes.
Any gap in the visual field corresponding to an area of the retina where no visual cells are present; this type of blind spot is as...
Spot, histo: See: Histo spot....
Spots in front of the eyes
Spots in front of the eyes: Also known as "floaters", blurry spots that drift in front of the eyes but do not block vision. The blur is the result of debris from the vitreous casting a shadow on the retina. The spot is the image formed by a deposit of protein drifting about in the vitreous, the cle...
Spots, Brushfield's: Speckled
iris. Little white spots that slightly elevated on the
surface of the iris and are arranged in a ring concentric
with the pupil. These spots occur in normal children but
are far more frequent in Down's syndrome (trisomy 21). They
were described in 1924 by Thomas...
Spots, Koplik's: Little spots
inside the mouth that are highly characteristic of the
early (prodromal) phase of measles (rubeola). The spots
look like a tiny grains of white sand, each surrounded by a
red ring. They are found especially on the inside of the
cheek (the buccal mucosa) opposi...