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...

    Growth and Plant Hormones
    Growth and Plant Hormones

    Plants, like animals, produce hormones to regulate plant activities, including growth. They need these hormones to respo..

    Population Regulation in an Ecosystem
    Population Regulation in an Ecosystem

    With regard to the population size of a species and what factors may affect them, two factors have been defined. They ar..

    Birth of a Human Baby
    Birth of a Human Baby

    Following nine months inside the mother's womb is the birth of the baby. Know the different stages of the birthing proce..

    Sensory systems
    Sensory Systems

    A sensory system is a part of the nervous system consisting of sensory receptors that receive stimuli from the internal ..

    takahē
    Takahē (Porphyrio hochstetteri)

    Meet the colorful takahē, an extremely rare flightless bird. Find out more about its unique features and why they matte..

    Biological Viruses
    Biological Viruses

    Viruses possess both living and non-living characteristics. This unique feature distinguishes them from other organisms...

    Related Articles...

    No related articles found

    See all Related Topics