Dictionary

sphingomyelinosis See histiocytosis, lipid.

sphygmomanometer Blood pressure cuff, an instrument for measuring blood pressure, particularly in arteries. Digital and manual models are available. The two basic types of manual sphygmomanometers are the mercury column and the gauge with a dial face. The manual sphygmomanometer in most frequent use today consists of a gauge attached to a rubber cuff that…

spider bite A bite from a spider. Bites from most spiders are irritating but not poisonous. Localized reddening and swelling are not unusual and should pass within a few days. A few spiders are poisonous, notably the black widow and brown recluse (brown fiddler) in the US. Bites from these spiders require emergency treatment, especially…

spider telangiectasia See spider vein.

spider vein A group of widened veins that can be seen through the surface of the skin. The wheeland-spokes shape of the veins resembles a spider. Also known as spider telangiectasia.

spina bifida A major birth defect and a type of neural tube defect that involves an opening in the vertebral column caused by the failure of the neural tube to close properly during embryonic development. (The neural tube is the structure in the developing embryo that gives rise to the brain and spinal cord.) Because…

spina bifida cystica See meningomyelocele.

spina bifida occulta A bony defect in the vertebral column that causes a cleft in that column. The cleft remains covered by skin. Treatment is usually not required.

spinal column See vertebral column.

spinal cord The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute…

spinal fusion A surgical procedure in which two or more of the vertebrae in the spine are united together so that motion no longer occurs between them. Spinal fusion may be done to treat a number of conditions, including scoliosis, deformity, fracture, and disc disease. Bone grafts are usually placed around the section of the…

spinal nerve One of the nerves that originates in the spinal cord. There are 31 pairs of spinal nerves: 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve.