Dictionary

synoviosarcoma See sarcoma, synovial.

synovitis Inflammation of the synovial membrane, the lining of the joints.

syphilis A sexually transmitted disease that is caused by Treponema pallidum, a spiral-shaped microscopic organism called a spirochete. The organism infects people by burrowing into the moist mucous membranes of the mouth or genitals. From there, the spirochete produces a nonpainful ulcer known as a chancre. There are three stages of syphilis. The first (primary)…

syphilis, congenital Infection of a fetus or newborn with syphilis. Syphilis in a fetus can cause deformity, particularly of the long bones, or death. Syphilis infection acquired at birth is also dangerous. See also TORCH screen.

syphilis test, RPR Rapid plasma reagin syphilis test, a blood test for syphilis that looks for an antibody that is present in the bloodstream when a patient has syphilis. A negative (nonreactive) RPR test is compatible with a person not having syphilis, but in the early stages of the disease, the RPR often gives false…

syringe A medical device that is used to inject fluid into, or withdraw fluid from, the body. A medical syringe consists of a needle attached to a hollow cylinder that is fitted with a sliding plunger. The downward movement of the plunger injects fluid; upward movement withdraws fluid. Medical syringes were once made of metal…

syringoma A benign (noncancerous) skin tumor that derives from eccrine cells, specialized cells related to sweat glands. The skin lesions of syringoma usually appear during puberty or adult life, and consist of small bumps 1 to 3 mm in diameter that form under the surface of the skin. The most frequent site is the eyelids…

systemic therapy Treatment that reaches cells throughout the body by traveling through the bloodstream.

systemic-onset juvenile chronic arthritis See arthritis, systemic-onset juvenile rheumatoid.

systemic-onset juvenile rheumatoid arthritis See arthritis, systemic-onset juvenile rheumatoid.

systolic Referring to the time at which ventricular contraction occurs, which is called systole. Systolic pressure is the maximum arterial pressure during contraction of the left ventricle of the heart. In a blood pressure reading, the systolic pressure is typically the first number recorded. For example, in a blood pressure of 120/80 (“120 over 80”),…

T Thymine, one member of the adenine-thymine (A-T) base pair in DNA.