Dictionary

sphenoid bone A prominent, irregular, wedgeshaped bone at the base of the skull. The sphenoid bone has been called the “keystone” of the cranial floor because it is in contact with all of the other cranial bones.

spherocytosis, hereditary A genetic disorder of the red blood cell membrane that is characterized by anemia, jaundice, and enlargement of the spleen (splenomegaly). Abbreviated HS. In HS, the red cells are smaller, rounder, and more fragile than normal. They have a spherical shape rather than the biconcave-disk shape of normal red cells. These fragile red…

sphincter A muscle that surrounds and, by its contraction, closes a normal opening such as that from the intestinal tract or the urinary tract. Damage to the anal and urethral sphincters can cause fecal and urinary incontinence, respectively. Sphincters tend to be ring-like and, when contracted, to constrict the opening. From the Greek for “that…

sphingolipidosis One of a group of hereditary diseases that involve overproduction or accumulation of fatty substances called sphingolipids in the brain and nervous system. See also Anderson-Fabry disease; Gaucher disease; GM1-gangliosidosis, histiocytosis, lipid; Krabbe disease; leukodystrophy; Tay-Sachs disease; Sandhoff disease.

snake stick See Aesculapius.

snakebite The bite of a snake, whether poisonous or not. Most snakes are not poisonous, but their bites can nonetheless cause painful puncture wounds that require treatment. If a snakebite victim knows a snake was poisonous, or if the person did not see or recognize the snake, he or she should immediately seek emergency treatment….

Snellen chart See chart, Snellen.

snoring A sound created by vibrations of the uvula and soft palate during sleep. During normal breathing, air passing through the throat en route to the lungs travels by the tongue, soft palate, uvula, and tonsils. When a person is awake, the muscles in the back of the throat tighten to hold these structures in…

social phobia A paralyzing fear of interacting with others. Symptoms include excessive blushing, sweating, trembling, rapid heartbeat, muscle tension, nausea, and extreme anxiety. Social phobia can occur in very young children or emerge at a later age. It can be disabling to a person’s work and social and family relationships. Many people with social phobia…

social worker A health professional who assists individuals and families with social or emotional issues. Within the medical system, a social worker might help uninsured families who need medical care find help; work with grieving parents, spouses, or other family members; provide individual therapy; or help patients find resources to meet their needs for personal…

socialization The learning process a child goes through as he or she learns how to interact appropriately with other people.

socialized medicine A medical system like that of a socialist country, in which medical facilities and payments are under government, rather than private, control. Most industrialized nations, including the US, have medical systems under some combination of state and private control. For examples, socialized medicine is practiced in Canada and Britain.