Jendrassik maneuver

The Jendrassik maneuver is a medical maneuver wherein the patient clenches the teeth, flexes both sets of fingers into a hook-like form, and interlocks those sets of fingers together. The tendon below the patient's knee is then hit with a reflex hammer to elicit the patellar reflex. The elicited response is compared with the reflex result of the same action when the maneuver is not in use. Often a larger reflex response will be observed when the patient is occupied with the maneuver: "A weak or apparently missing reflex could be triggered by afferent activity resulting from such muscle tension. This is the true explanation for the maneuver, not a diversion of the patient’s attention – a misconception that can be heard even today."[1] This effect was first observed in the late 19th century by Hungarian physician Ernő Jendrassik, after whom it was named.

The Jendrassik maneuver to reinforce knee-jerk.

This maneuver is particularly useful in that even if the patient is aware of the maneuver's purpose, it still functions properly.[2]

The maneuver can also be used to distract patients when performing other tests or procedures and any suitable distraction may be used; for example when looking for Romberg's sign.[3]