The Achilles tendon reflex, also known as the ankle reflex test, is a basic test used to assess the integrity of the S1 nerve root, which innervates the lower leg and foot. Here’s a detailed look at the reflex and its clinical significance:
Mechanism
Tapping the Achilles Tendon: The test involves tapping the Achilles tendon just above the heel, which stretches the calf muscles (gastrocnemius and soleus).
Stimulation of Muscle Spindles: This stretch activates muscle spindles in the calf muscles, sending sensory signals to the spinal cord.
Reflex Arc Activation:
The sensory signals stimulate motor neurons in the spinal cord, which then send impulses back to the calf muscles, causing them to contract.
This contraction results in a plantar flexion movement of the foot, which is the expected response.
