Increased tone in one or more muscles, causing them to feel tight; the affected part of the body becomes stiff and inflexible. Causes include muscle injury, arthritis in a nearby joint, a neurological disorder, or stroke. Rigidity of the abdominal muscles is a sign of peritonitis. (See also spasticity.)
Sti?ness, resistance to movement. The term is often used in NEUROLOGY – for example, limb rigidity is a sign of PARKINSONISM. Smooth rigidity is described as being ‘plastic’ and jerky rigidity as ‘cogwheel’.
n. (in neurology) resistance to the passive movement of a limb that persists throughout its range. It is a symptom of *parkinsonism. The smooth resistance through the whole range of movement is also known as lead-pipe rigidity; with superimposed tremor, as in parkinsonism, it is called cogwheel rigidity. Compare spasticity.
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