Why do doctors check your reflexes in your knee?
Medical author Dr Janice Rachel Mae explains that doctors routinely use reflex tests to check if there are any problems in the nervous system involved in movement, nerve functioning or health of the connective tissue in the knee or leg.
How do you test someone’s knee reflex?
Tap the spot right below your kneecap with the side of your hand. Feel your knee to find a slight gap between the bottom of your kneecap and the top of your shin bone. Gently tap that space with the side of your hand, or have a friend do it for you. If you have a medical reflex hammer, that’s even better!
What does it mean if you fail the knee reflex test?
The normal response is a ‘knee jerk’. This is an example of a reflex, which is an involuntary muscular response elicited by the rubber hammer tapping the associated tendon. When reflex responses are absent this could be a clue that the spinal cord, nerve root, peripheral nerve, or muscle has been damaged.
What are doctors looking for when they test your reflexes?
By checking your muscle strength, your reflexes, and your sensation (feeling), your doctor can tell whether there is pressure on a nerve root coming from your spinal column. He or she can often also tell which nerve root is involved.
What is the doctor checking when he hits your knee?
The most familiar reflex is the knee jerk, when a healthcare provider taps on the tendon below your knee with a reflex hammer and that leg kicks out. The stimulus (the hammer) results in a signal being sent via a sensory nerve to the spinal cord.
Why is knee jerk reflex important?
In reaction these muscles contract, and the contraction tends to straighten the leg in a kicking motion. Exaggeration or absence of the reaction suggests that there may be damage to the central nervous system. The knee jerk can also be helpful in recognizing thyroid disease.
Why is the knee-jerk reflex important?
What instrument is used to test knee reflex?
The penlight is typically used to examine the eyes, nose and throat. Percussion Hammer – tool used to test neurologic reflexes. The head of the instrument is used to test reflexes by striking the tendons of the ankle, knee, wrist and elbow.
What is the normal knee reflex?
The normal knee-jerk reflex involves no input to or from the brain. The normal knee-jerk or, “patellar jerk,” reflex is elicited when the knee is tapped below the knee cap (patella). Sensors that detect stretching of the tendon of this area send electrical impulses back to the spinal cord.
What is the cause of no reflex response in the knee?
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.
What causes no knee reflex?
Causes of an absent knee and ankle reflex with extensor plantars implies a mixed upper and lower motor neurone lesion, and causes include: subacute combined degeneration of the spinal cord. motor neurone disease.