<prompt> Root value of ankle jerkL3 L4L4 L5S1 S2S3 S4  <response>: The ankle jerk reflex, also known as the Achilles reflex, occurs when the Achilles tendon is tapped while the foot is dorsiflexed. This reflex is mediated by the S1 spinal segment of the spinal cord. Ref: guyton and hall textbook of medical physiology 12 edition page number: 774,775,776 