The heel reflex, more accurately known as the ankle jerk reflex or Achilles reflex, is a diagnostic test that assesses the function of specific nerves and muscles in the leg.
Understanding the Ankle Jerk Reflex
The ankle jerk reflex is a type of stretch reflex. This means it's an involuntary muscle contraction in response to stretching the muscle. Specifically, it tests the function of the gastrocnemius muscle (a major calf muscle) and the nerve that supplies it.
How the Heel Reflex is Tested
The ankle jerk reflex, or heel reflex, is elicited by a healthcare professional using the following steps:
- The patient is usually seated with their legs dangling or the foot dorsiflexed (bent upwards)
- The examiner taps the Achilles tendon (which connects the calf muscle to the heel bone) with a reflex hammer.
What a Normal Response Looks Like
A normal response is plantar flexion of the foot – the foot moves downwards. This indicates that the nerve pathway and muscle are functioning correctly.
What Abnormal Responses Might Indicate
- Absent or diminished reflex: This could suggest nerve damage, muscle problems, or hypothyroidism.
- Exaggerated reflex: This might indicate an upper motor neuron lesion (damage to the brain or spinal cord).
Summary of Heel Reflex Components
| Component | Description |
|---|---|
| Medical Term | Ankle Jerk Reflex, Achilles Reflex |
| Mechanism | A stretch reflex, testing the nerve and muscle response. |
| Procedure | Tap the Achilles tendon while the foot is dorsiflexed. |
| Normal Response | Plantar flexion (foot moves downwards). |
| Abnormal Response | Absent, diminished, or exaggerated reflexes can indicate various neurological or muscular issues. |
