Achilles Reflex

Achilles reflex, is obtained by tapping the Achilles tendon; the motor effect is plantar flexion of the foot (contraction of the triceps surae muscle). The reflex center in the spinal cord extends from the fifth lumbar to the second sacral segments inclusive. The Achilles reflex can be conveniently elicited with the patient kneeling and feet hanging down (Babinski's method). In the initial stages of tabes, the Achilles reflex usually disappears earlier than the knee reflexes. Absence of the Achilles reflex is a very important symptom in inflammation of the sciatic nerve (organic changes). Increased Achilles reflex in cases of pyramidal tract involvement reaches the degree of foot clonus.