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One type of increase in muscle tone at rest; characterized by increased resistance to passive stretch, velocity dependent and asymmetric about joints ( i.e., greater in the flexor muscles at the elbow and the extensor muscles at the knee). Exaggerated deep tendon reflexes and clonus are additional manifestations. SEE ALSO: clasp-knife s..
- clasp-knife s. initial increased resistance to stretch of the extensor muscles of a joint that give way rather suddenly allowing the joint then to be easily flexed; the rigidity is due to an exaggeration of the stretch reflex. SEE ALSO: lengthening reaction. SYN: clasp-knife effect, clasp-knife rigidity.
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spas·ti·ci·ty spa-'stis-ət-ē n, pl -ties a spastic state or condition esp muscular hypertonicity with increased tendon reflexes
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n.
resistance to the passive movement of a limb that is maximal at the beginning of the movement and gives way as more pressure is applied. It is a symptom of damage to the pyramidal system in the brain or spinal cord. It is usually accompanied by weakness in the affected limb (see spastic paralysis). Compare rigidity.
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spas·tic·i·ty (spas-tisґĭ-te) the state of being spastic; see spastic (def. 2).Medical dictionary. 2011.