Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «S»:
Stereotactic radiotherapy: Radiation therapy in which a
number of precisely aimed beams of ionizing radiation coming from
different directions meet at a specific point, delivering the
radiation treatment to that spot....
Surgery in which a system of three-
dimensional coordinates is used to locate the site to be operated on.
Stereotactic surgery is used in neurosurgery (and neurological research)
for locating points within the brain. This is usually done by using an external, three-dimension...
Stereotaxis: Use of a computer and scanning devices
three-dimensional pictures. This method can be used to direct a
radiation, or the insertion of radiation implants....
Sterilization, female surgical
surgical: Female surgical sterilization blocks (or removes part or all of)
the fallopian tubes
so the egg cannot travel to the uterus. The procedure is done by various surgical techniques, usually under general anesthesia.
Complications are rare but can includ...
Sterilization, male surgical
Sterilization, male surgical: Male surgical sterilization is done by vasectomy which involves sealing, tying or cutting a man's vas deferens, the tube which otherwise would carry the sperm from the testicle to the penis.
Vasectomy is a relatively short operation, usually takes under 30 minutes, and...
Sterilization, surgical: Surgical sterilization is a contraceptive option for people who do not want children in the future. It is considered permanent because reversal requires major surgery that is often unsuccessful.
Female sterilization blocks the fallopian tubes so the egg cannot travel to the ...
Sternal rib: One of the first 7 pairs of ribs. A rib is said to be a "sternal" rib or a "true" rib if it attaches to the sternum (the breast bone).
All 12 pairs of ribs attach to the building blocks of the spine (vertebrae) in the back. The 12 pairs of ribs consist of:
Sternal or true ribs: The firs...
Sternum: Anatomic name for the breast bone, the long flat bone in the upper middle of the front of the chest.
The sternum articulates (comes together) with the cartilages of the first seven ribs and with the clavicle (collar bone) on either side.
The sternum consists of three parts: the manubrium (t...
Sternutation: Sneezing; the sound of sneezing.
When we sneeze, air is expelled with force from the nose (and from the mouth, if it is open) due to a spasmodic contraction of the chest muscles and diaphragm. A sneeze is often triggered by irritation of the mucous membrane of the nose or less often b...
Sternutator: Something that causes a sneeze. From the Latin sternutatio (sneeze). See also: Sternutation....
Steroid: A general class of chemical substances that are structurally related to one another and share the same chemical skeleton (a tetracyclic cyclopenta[a]phenanthrene skeleton).
Many hormones, body constituents, and drugs are steroids. Thus, the term steroid may carry many meanings. For exampl...
Steroid abuse: Use of substances containing
anabolic steroids to increase muscle mass. Such steroids
can have many side effects when misused, including
psychiatric problems, liver tumors, reduction in the size
of the male genitals and sterility, and heart damage.
Steroid, designer: See: Designer steroid....
Stethoscope: An instrument used to transmit low-volume sounds such as the heartbeat (or intestinal, venous, or fetal sounds) to the ear of the listener. A stethoscope may consist of two earpieces connected by means of flexible tubing to a diaphragm placed against the skin of the patient.
Stevens-Johnson syndrome: A serious systemic (bodywide) allergic reaction with a characteristic rash involving the skin and mucous membranes, including the buccal mucosa (inside of the mouth). The disease is due to a hypersensitive (allergic) reaction to one of a number of immunologic stimuli includ...