clasp-knife rigidity

rigidity

 [rĭ-jid´ĭ-te]

inflexibility or stiffness.

clasp-knife rigidity increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease. Called also clasp-knife reflex.

cogwheel rigidity tension in a muscle that gives way in little jerks when the muscle is passively stretched; seen in parkinson's disease.

decerebrate rigidity see decerebrate rigidity.

decorticate rigidity see decorticate rigidity.

paratonic rigidity an intermittent abnormal increase in resistance to passive movement in a comatose patient.

clasp-knife spas·tic·i·ty

a type of increased muscle tone due to a pyramidal tract lesion, in which abnormally increased resistance to passive stretch of a muscle abruptly decreases; typically, this appears near the end of the range of joint excursion.
See also: lengthening reaction.

Synonym(s): clasp-knife effect, clasp-knife rigidity

clasp-knife spas·ti·ci·ty

, clasp-knife rigidity (klaspnīf' spas-tis'i-tē, ri-jid'i-tē)

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.

clasp-knife spas·ti·ci·ty

, clasp-knife rigidity (klaspnīf' spas-tis'i-tē, ri-jid'i-tē)

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.

rigidity

inflexibility or stiffness.

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clasp-knife rigidity

increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease.

cogwheel rigidity

tension in a muscle that gives way in little jerks when the muscle is passively stretched.

lead-pipe rigidity

posture adopted when the rigidity of the limb is maintained equally throughout the passive flexion.

rigidity reflex

the state of immobility generated in female animals, especially those in estrus, when they make physical contact with a male.