Lower Extermity Reflexes

This video demonstates the lower extremity reflex examination. To perform the Patellar Tendon or Knee Jerk Reflex, have the patient seated with her legs dangling and off the floor. Tap briskly over the patellar tendon, inferior to the patella with the knee flexed. You should observe knee extension. Alternatively, this reflex can be performed with the patient supine by supporting the knee in slight flexion. To perform the medial hamstring reflex on a patient in the seated position, slightly externally rotate and abduct the thigh. Then, place your finger over the tendons of semimembranosus and semitendinosus, the medial hamstring tendons, and tap briskly. You should observe contraction of the medial hamstrings or knee flexion. To perform the Achilles tendon or ankle jerk reflex, have the patient seated with her legs dangling and off the floor. Place the foot in slight dorsiflexion and tap briskly over the Achilles tendon. You should observe plantarflexion. Alternatively, this maneuver can be performed with the patient kneeling, or with the patient supine, again by ensuring slight dorsiflexion of the ankle prior to heel strike.