Dictionary > Achilles reflex

Achilles reflex

Definition
noun, plural: Achilles reflexes
A stretch reflex wherein the foot jerks towards the plantar surface by reflex as a response to a tap on the Achilles tendon while the foot is dorsiflexed
Supplement
A stretch reflex is a reflex reaction characterized by muscle contraction due to the stimulation of the muscle proprioceptors. When the muscle is stretched, the body reacts by resisting the stretch by reflex. Some of the stretch reflexes are jaw jerk reflex, biceps reflex, brachioradialis reflex, triceps reflex, patellar reflex, and ankle jerk reflex.
The Achilles reflex is a form of stretch reflex in which the foot jerks towards its plantar surface when the Achilles tendon is tapped while the foot is dorsiflexed. It is also applied in neurologic tests to examine the nerve status and the gastrocnemius muscle. The S1 spinal segment of the spinal cord controls this reflex. It is monosynaptic, meaning it involves only one synapse between the sensory neuron and the motor neuron. The test is done by tapping the Achilles tendon with a reflex hammer. A positive result is a brisk plantarflexion of the foot. The absence of or a slight Achilles reflex reaction may indicate a medical condition, e.g. lumbar herniated disk syndrome, hypothyroidism, sciatic neuropathy, hypothermia, etc.
Synonym(s):

  • ankle jerk reflex

See also:

  • stretch reflex


  • You will also like...

    Peppered moth ("Biston betularia") melanic and light form
    Examples of Natural Selection

    Darwin's Finches are an example of natural selection in action. They are an excellent example of the way species' gene p..

    Geological Periods
    Geological Periods

    Geological periods is a study guide that cites the different geological periods on Earth's timeline. Each has a brief ov..

    Kidneys
    Kidneys and Regulation of Water and Inorganic Ions

    The kidneys are responsible for the regulation of water and inorganic ions. Read this tutorial to learn about the differ..

    Biological Cell Defense
    Biological Cell Defense

    Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..

    Neural Control Mechanisms
    Neural Control Mechanisms

    Neurons generate electric signals that they pass along to the other neurons or target tissues. In this tutorial, you wil..

    New Zealand - Biodiversity fauna
    New Zealand’s Biodiversity

    Find out more about New Zealand's unique biodiversity by exploring a range of different ecosystems and the key role of s..

    Related Articles...

    No related articles found

    See all Related Topics