Category: S

A ferritin-containing normoblast in the bone marrow. Sideroblasts constitute from 20% to 90% of normoblasts in the marrow. The ferritin gives a positive Prussian-blue reaction, indicating the iron is ionized and not bound to the heme protein.  

A lateral recumbent position in which the individual rests on the right or left side, usually with the knees slightly flexed. This position may be used in persons with mild forms of sleep apnea, in some patients with dysphagia, and in patients predisposed to sacral decubitus ulcers, among other conditions.  

A device for positioning the patient with central nervous system dysfunction in a lateral recumbent position in order to reduce decerebrate posturing and counteract the effects of the tonic labyrinthine (supine) reflex.  

A transient form of motion sickness occurring in space travelers.  

A test that measures the propensity of red blood cells to sickle under conditions of reduced oxygen tension. The test may be performed by adding sodium metabisulfite to a drop of blood and examining the blood smear microscopically. Hemoglobin electrophoresis is an alternative test for sickle cell disease.  

The tendency of red blood cells to change from a biconcave to an arched shape when oxygen tensions are low. The deformity results from the polymerization of abnormal hemoglobin molecules, such as hemoglobin S. Sickled red blood cells clog small blood vessels, producing tissue ischemia or infarction.  

Brothers and sisters of a single family.  

A hissing sound made while speaking.  

A fistula into the salivary gland.  

Closure of a salivary duct.