1. The dominant peak in the record of an action potential or electroencephalogram. 2. The narrow vertical tracing left on an electrocardiogram by the impulse generator of an electronic pacemaker. 3. A needle used to puncture an object, e.g., a bag of intravenous fluids or a cyst, permitting fluids within the object to flow out. 4. Any of the structural units that facilitate attachment of viruses to host cell receptors.
Electroencephalic evidence of grand mal seizures.
(spĭl) [Old English spillan, to squander] 1. To flow out of or release; in medicine, said of a substance that cannot be maintained in the body by one of its organs, esp. the kidneys. In diabetes mellitus, for example, the kidneys spill sugar into the urine. In the nephrotic syndrome, they spill protein. 2. An overflow.
radioactive s. A release of radioactive materials into the environment.
Tools and equipment to contain, absorb, and dispose of hazardous substances (such as body fluids or cytotoxic medications) in clinics and hospitals. The kit includes personal protective equipment (such as gloves, goggles, gowns, masks), sterilized sheets, disposable absorbent materials, and leakproof containers.
(spĭl′way) The contour of the teeth that allows food to escape from the cusps during mastication.
(spĭ′nă) pl. spinae [L. spina, thorn] 1. A spinelike protuberance. 2. The spine.
s. bifida Spina bifida cystica.
s. bifida cystica A congenital defect in the walls of the spinal canal caused by a lack of union between the laminae of the vertebrae during embryonic development. The lumbar portion is the section chiefly affected. It is found in approx. 18 of every 100,000 births. Like other neural tube defects, it can be prevented with folic acid supplementation (800 mcg daily) taken by women before and during pregnancy. The consequences of this defect include urinary incontinence, saddle or limb anesthesia, disturbances in gait, and structural changes in the pelvis. SYN: rachischisis.
s. bifida occulta A failure of the vertebrae to close without hernial protrusion.
(spī′năl) [L. spinalis] Pert. to the spine or spinal cord. SYN: rachial; rachidial.
spinal cavernous malformation
Part of the central nervous system, the spinal cord is an ovoid column of nerve tissue 40 ...