What Is an Achilles Reflex?
Also known as the ankle jerk reflex, the Achilles reflex is a response to a strike to the back of the ankle. It can be demonstrated by hitting the Achilles tendon when the ankle when the foot is flexed upward at the ankle joint so that the top of the foot is brought toward the shin. This reaction is seen as a sudden downward jerk of the foot from the dorsiflexed position as caused by a contraction of the calf muscles. The Achilles reflex may be tested in a medical setting to determine whether the sciatic nerve, which crosses the back of the ankle just deep to the Achilles or calcaneal tendon, is functioning properly.
