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Pendular Knee Jerk- clinical significance

What is pendular knee jerk?
More than 3 oscillations equidistant from the neutral position is observed after eliciting knee jerk and
Method of elicitation
Pendular reflexes are best observed when the patient's lower legs are allowed to hang and swing freelly off the end of an examining table.
Pendular reflexes are not brisk but they involve less damping of the limb movement than is usually observed when a deep tendon reflex is elicited.
Patients with cerebellar injury may have a knee jerk that swings forwards and backwards several times.
A normal or brisk knee jerk would have little more than one swing forward and one back.

Clinical significance 
It is seen in cerebellar lesion,which is characterised by marked hypotonia.
Innervation of knee jerk
The knee jerk reflex is mediated by the L3 and L4 nerve roots, mainly L4.