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How to test the kneecap reflex

If you’ve ever had a physical in the doctor’s office, they probably knocked on your knee with a small rubber mallet and made your leg kick out. This simple test is intended to check the reflexes in the leg, or how fast signals move between your nerves, spinal cord and muscles. If you are curious about testing your own squat (or patellar) reflex, you can easily do it with just your hand or a rubber reflex hall! If you have any concerns about your reflexes, call your doctor. They can do more thorough tests to check for any problems.


[[[[Edit]Test your own squat reflex

  1. Sit on the edge of a bed or table with your legs dangling. Find a surface that is high enough so that you can let your legs dangle freely when you sit on it. Keep your knees bent at a 90 ° angle when sitting.[1]
    Test Knee Jerk Reflex Step 01.jpg
    • Your legs must be able to swing for you to see the reflex at work.
    • You may also be able to help yourself lift your knee slightly by placing one of your hands under it.
  2. Point to the spot just below the knee pad with the side of your hand. Feel your knee to find a small space between the bottom of the kneecap and the top of your leg bone. Gently tap that space with the side of your hand, or have a friend do it for you.[2]
    Test Knee Jerk Reflex Step 02.jpg
    • If you have a medical reflex hammer, it’s even better! These hammers are specially designed to hit the tendon exactly without causing pain. Do not use any other type of hammer, otherwise you may injure yourself.
    • Alternatively, you can cup your hand and keep your fingers close together. Rest your wrist on the kneecap and swing your fingers down to hit the door.
  3. Watch out for the lower leg to kick forward a little. When you tap the knee with the side of the hand or a reflex hammer, the muscles in the thigh are tensed briefly. Watch out for your leg to kick out a bit and then rest.[3]
    Test Knee Jerk Reflex Step 03.jpg
    • You may feel a slight “tickling” feeling in the leg when you hit the tendon.
    • You can get a stronger reaction if you use a proper medical reflex hammer.
    • If your leg does not respond at all or has a very slow reaction, it may be a sign of nerve damage in the leg or lower spine. If this happens, do not panic – it is possible that you just did not do the test correctly. Call your doctor if you are worried.

[[[[Edit]Get a neurological examination

  1. Contact your doctor if you are worried about a neurological problem. Reflex testing is a standard part of most general physical exams. However, your doctor may also recommend reflex tests if they suspect you have a neurological problem, such as a disease or injury that is affecting your nervous system.[4] Ask your doctor if you need a reflex test.
    Test Knee Jerk Reflex Step 04.jpg
    • They may also recommend a patellar reflex test if they suspect damage to the lumbar nerves.[5]
  2. Talk to your doctor about your health history. Let your doctor know if you have had any injuries or illnesses that may affect your reflexes, or if you have had any symptoms you are worried about. This will help them determine the source of the problem. Common symptoms of neurological disease or nerve damage include:[6]
    Test Knee Jerk Reflex Step 05.jpg
    • Sudden or persistent headache
    • Firmness, tingling or weakness in any part of the body
    • Changes in vision
    • Shaking, involuntary movements or loss of coordination
    • Back pain that radiates to other parts of the body, such as the legs
    • Difficulty thinking, remembering or concentrating
  3. Let them test all your deep tendon reflexes. In addition to testing your knee reflex, your doctor or neurologist will test the reflexes in other parts of the body. As with the squat reflex, they test these reflexes by gently tapping your tendons with a rubber mallet.[7] Other common deep tendon reflex tests include:[8]
    Test Knee Jerk Reflex Step 06.jpg
    • The biceps and triceps reflexes. For these tests, your doctor will press on the tendons near your elbow to get the muscles in your upper arm pulled.
    • Brachioradialis reflex. The doctor will tap a tendon above the wrist to make your forearm flexible.
    • Ankle reflex. This test involves tapping your Achilles tendon (the tendon that connects your heel to your calf muscles) with the hammer to make your foot smoke.
  4. Consent to other tests to determine the source of the problem. If your doctor suspects a neurological problem, they may refer you to a specialist, called a neurologist, for further testing. The neurologist asks you about your health history and performs a variety of tests. They might:[9]
    Test Knee Jerk Reflex Step 07.jpg
    • Test your ability to feel a soft cloth, some bright needles or objects with different temperatures.
    • Ask questions to check your basic language and math skills, or test your ability to remember basic information.
    • Check your vital signs, such as your heart rate, respiratory rate, body temperature and blood pressure.


  • It is possible that you can improve your reflexes with exercise. For example, you may be able to develop faster reflexes in your legs and feet by practicing running or kicking.[10] If you have any health problems, ask your doctor what type of exercise is safe for you.
  • Ask a friend or family member to test your reflexes if you have trouble triggering them yourself.
  • Hook your fingers together and try to pull them apart to help distract you from the test. This way you get more accurate results.


  1. http://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/pd/pstep56.htm
  2. https://faculty.washington.edu/chudler/chreflex.html
  3. https://www.dartmouth.edu/~dons/part_1/chapter_8.html
  4. https://www.ncbi.nlm.nih.gov/books/NBK348940/
  5. https://www.uofmhealth.org/health-library/hw47243
  6. https://www.hopkinsmedicine.org/health/conditions-and-diseases/overview-of-nervous-system-disorders
  7. https://www.ncbi.nlm.nih.gov/books/NBK348940/
  8. https://informatics.med.nyu.edu/modules/pub/neurosurgery/reflexes.html
  9. https://www.ncbi.nlm.nih.gov/books/NBK348940/
  10. https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=1&ContentID=562

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