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a sudden reflex or involuntary movement.
Achilles jerk (ankle jerk) plantar extension of the foot elicited by a tap on the achilles tendon, while the patient is seated on a bed or chair, with feet hanging freely; called also Achilles reflex and triceps surae jerk or reflex.
biceps jerk biceps reflex.
elbow jerk involuntary flexion of the elbow on striking the tendon of the biceps or triceps muscle.
jaw jerk jaw-jerk reflex.
knee jerk see knee jerk.
tendon jerk tendon reflex.
triceps surae jerk ankle jerk.
a spasmodic contraction of the temporal muscles following a downward tap on the loosely hanging mandible.
an abnormal reflex elicited by tapping the chin with a rubber hammer while the mouth is half open and the jaw muscles are relaxed. A quick snapping shut of the jaw implies damage to the area of cerebral cortex governing motor activity of the fifth cranial nerve. Also called chin reflex, chin-jerk reflex, mandibular reflex.
A colloquial term for reflex.
Achilles jerkAchilles tendon reflex.
ankle jerkSee: ankle clonus reflex
biceps jerkSee: biceps reflex
elbow jerkTriceps reflex.
jaw jerkChin reflex.
The extension of the lower leg upon striking the patellar tendon when the knee is flexed at a right angle. Knee jerk is absent in locomotor ataxia, infantile paralysis, meningitis, destructive lesions of the lower part of the spinal cord, and certain forms of paralysis. It is increased in lesions of pyramidal areas, brain tumors, spinal irritability, and cerebrospinal sclerosis.See: knee-jerk reflex
The contraction of a muscle after tapping its tendon.