Final answer:
The Jendrassik maneuver is used to enhance the patellar reflex by providing a distraction through voluntary muscle contraction in remote parts of the body, which often leads to an exaggerated reflex when the patellar tendon is struck.
Step-by-step explanation:
The Jendrassik maneuver is a technique used to enhance or bring out patellar reflexes that might be difficult to elicit under normal conditions. During this maneuver, a patient might clench their teeth or interlock their fingers and pull apart, creating a distraction which can enhance the motor neuron reflex pathways. When the patellar tendon is struck during this process, the usual involuntary contraction of the quadriceps femoris muscle that causes the leg to kick (the patellar reflex) may be exaggerated because of the increased facilitation of spinal cord neurons due to the Jendrassik maneuver.