What is normal reflex?

Asked By: Tunde Lleti | Last Updated: 24th March, 2020
Category: medical health brain and nervous system disorders
4.2/5 (50 Views . 27 Votes)
Definition. In a normal person, when a muscle tendon is tapped briskly, the muscle immediately contracts due to a two-neuron reflex arc involving the spinal or brainstem segment that innervates the muscle. By convention the deep tendon reflexes are graded as follows: 0 = no response; always abnormal.

Click to see full answer


Beside this, can brisk reflexes be normal?

A normal response means your neurons respond to the tap from a reflex hammer with enough contraction (about two times). 3: brisk reflexes (more hyper reflexive than normal) 2: normal response. 1: little response (hypo reflexive)

One may also ask, what does it mean if your reflexes are absent? When reflex responses are absent this could be a clue that the spinal cord, nerve root, peripheral nerve, or muscle has been damaged. When reflex response is abnormal, it may be due to the disruption of the sensory (feeling) or motor (movement) nerves or both.

Correspondingly, what do deep tendon reflexes tell you?

Deep tendon reflex also usually refers to this sense. A deep tendon reflex is often associated with muscle stretching. Tendon reflex tests are used to determine the integrity of the spinal cord and peripheral nervous system, and they can be used to determine the presence of a neuromuscular disease.

What causes loss of reflexes?

Peripheral neuropathy is today the most common cause of absent reflexes. The causes include diseases such as diabetes, alcoholism, amyloidosis, uremia; vitamin deficiencies such as pellagra, beriberi, pernicious anemia; remote cancer; toxins including lead, arsenic, isoniazid, vincristine, diphenylhydantoin.

26 Related Question Answers Found

What will happen if we don't have reflex action?

Any destruction of nerves, either by trauma, or by peripheral nerve diseases can cause loss of reflexes. That too destruction of more than a certain number of nerves. Also, compression or severance of the interneurons can also lead t the loss of reflexes.

Why do doctors check reflexes?

Reflex tests are performed as part of a neurological exam, either a mini-exam done to quickly confirm integrity of the spinal cord or a more complete exam performed to diagnose the presence and location of spinal cord injury or neuromuscular disease. Deep tendon reflexes are responses to muscle stretch.

How can I improve my reflexes?

Seven ways to improve your reflexes
  1. Pick a sport, any sport – and practise. What exactly do you want to improve your reflexes for?
  2. Chill out. Your reaction time is always going to be slower if you're too tense.
  3. Eat a lot of spinach and eggs.
  4. Play more videogames (no, really)
  5. Use your loose change.
  6. Playing ball.
  7. Make sure you get enough sleep.

What does it mean when your knee doesn't reflex?

Continual jerks after the tap can indicate cerebellar disease. If there is no response to the knee tap, it may indicate nerve damage. One side of the body reacts slower to a reflex test - If your reflexes are slower on one side it may indicate early onset of progressive disease, or localized nerve damage.

How do you test your reflexes?


The knee jerk reflex is one that you may have had tested at a check up at the doctor's office. In this test, the doctor hits your knee at a spot just below your knee cap and your leg kicks out. Try it! Have a partner sit with his or her legs crossed so that his leg can swing freely.

What is an overactive reflex?

Hyperreflexia is defined as overactive or overresponsive reflexes. Examples of this can include twitching or spastic tendencies, which are indicative of upper motor neuron disease as well as the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways (disinhibition).

How do reflexes work in the nervous system?

The simplest circuits in the nervous system are reflexes. A reflex is an automatic reaction to a stimulus. A stimulus is something that causes an action. In a simple reflex, a neuron brings information about a stimulus to the brain or spinal cord and connects with a motor neuron.

Does age affect reflexes?

Reflexes do slow with age. Physical changes in nerve fibers slow the speed of conduction. But the effect of age on reflexes and reaction time varies greatly from person to person. You can actually slow down—even reverse—the effects of aging by staying physically active.

What nerve is tested for triceps reflex?

The triceps reflex is mediated by the C6 and C7 nerve roots, predominantly by C7. With the lower leg hanging freely off the edge of the bench, the knee jerk is tested by striking the quadriceps tendon directly with the reflex hammer.

What causes decreased deep tendon reflexes?


256 Possible Causes for Deep Tendon Reflexes Absent or Decreased
  • Vitamin B12 Deficiency.
  • Ataxia Telangiectasia.
  • Glycogen Storage Disease Type 4.
  • Smith-Magenis Syndrome.
  • Familial Hypobetalipoproteinaemia Type 1.
  • Neuropathy.
  • Polyneuropathy.
  • Delirium.

What controls deep tendon reflexes?

The deep tendon reflexes are mediated by a monosynaptic arc. The afferent limb is provided by sensory fibers, which innervate muscle spindles. These fibers project centrally toward the spinal cord and synapse with alpha motor neurons in the ventral horn.

Why are reflexes important?

It is important that reflexes occur without the need for thinking about them because there are things that happen to your body and forces acting in your body when you move that need to be responded to very quickly. Reflexes allow your body to react in ways that help you to be safe, to stand upright, and to be active.

What nerve is tested in the biceps reflex?

Specifically, the test activates the stretch receptors inside the biceps brachii muscle which communicates mainly with the C5 spinal nerve and partially with the C6 spinal nerve to induce a reflex contraction of the biceps muscle and jerk of the forearm.

What is a positive Babinski sign?

In adults or children over 2 years old, a positive Babinski sign happens when the big toe bends up and back to the top of the foot and the other toes fan out. This can mean that you may have an underlying nervous system or brain condition that's causing your reflexes to react abnormally.

What set of muscles contracts to cause the leg to jerk when the patellar reflex is tested?


One of the several positions that a subject may take for the test is to sit with knees bent and with one leg crossed over the other so that the upper foot hangs clear of the floor. The sharp tap on the tendon slightly stretches the quadriceps, the complex of muscles at the front of the upper leg.

What does it mean when you have no reflex in your ankle?

Absent ankle jerk
It is classically delayed in hypothyroidism. This reflex is usually absent in disk herniations at the L5—S1 level. A reduction in the ankle jerk reflex may also be indicative of peripheral neuropathy.

What does no reflex in left leg mean?

The strength of the reflex response should be the same for both sides of the body. If the response is weak, or absent, that may indicate damage to the nerves. The nerve roots that exit the spine to form the sciatic nerve are extremely sensitive. Symptoms of sciatica are pain, numbness, tingling and weakness in the leg.