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Testing a person's muscle reflexes is done to assess how their central and peripheral nervous system is functioning. The way your muscles respond to stimulation can tell a doctor a lot about the health of your brain, spinal cord, and nerves. To test a person's reflexes, a doctor will tap a tendon with a reflex hammer. When this light pressure is applied at just the right spot, signals are sent to the muscle to contract. If the muscle doesn't contract normally, then the doctor will need to do further work to find the cause of this problem. [1]

Part 1
Part 1 of 3:

Gathering Supplies and Finding the Right Position

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  1. There are a variety of styles of reflex hammers to choose from. Some are light and small, and are designed to be swung with a small amount of force. Others are slightly weighted and use gravity to exert force onto the tendon. These hammers are available from medical supply businesses and online retailers.
    • The head of a reflex hammer is made of rubber. This helps to ensure that it does not hurt when the hammer taps a tendon.
  2. There are a wide variety of muscle reflexes that can be tested. The most common is the knee but any joint or large muscle can be assessed. Some reflexes that are usually tested during neurological exams include: [2]
    • Ankle
    • Knee
    • Abdomen
    • Forearm
    • Biceps
    • Triceps
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  3. When testing a person's reflexes, you will need to tap directly on the tendon that connects the bone and muscle you want to test. Feel the area where the tendon is normally located so that you can find its exact position. The tendon will feel like a tight strip of tissue under the surface of the skin.
    • For instance, if you want to test knee reflexes, you have to tap on the patellar tendon. This tendon is located just below the knee cap. Feel the bottom of the knee cap and, if necessary, have the person move their knee to make the tendon more visible.
  4. When testing reflexes, you need to allow the muscle to move freely once it is stimulated. [3] Make sure it is in a position where it is not flexed but when it does flex it will not be hindered. For example, if you are testing the reflexes of the knee, the person should be seated on an exam table with their legs hanging down freely.
    • If you are testing the bicep, allow the person to sit down and rest their arm in their lap. In this position the elbow should be bent a bit more than 90 degrees.
  5. While it is not a common practice, you can test your own reflexes. Since reflexes are involuntary, as long as you position the muscle properly and tap the proper location, your muscle should respond.
    • It may be difficult for you to get the reflex hammer into the proper position to test certain reflexes. For example, the achilles tendon would be difficult to test on your own body.
    • Testing your own reflexes is a good way to practice your technique for reflex testing.
    • If you have tried to test your reflexes yourself and you now have concerns about your health, go to a doctor to have the test done again. Having a doctor do reflex testing on you is more reliable than you doing it on yourself.
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Part 2
Part 2 of 3:

Causing the Muscle to Contract

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  1. If you are using a small, light hammer, hold it lightly between your thumb and forefinger. A weighted hammer can be held with the whole hand but the grip on this type of hammer should be light as well.
    • Holding the hammer lightly ensures that you do not apply too much force when you tap the tendon.
  2. Reflex testing only requires a single impact with the hammer. Move the hammer and your wrist in a 45 to 60 degree arc towards the tendon. This stroke should be done quickly and firmly, tap the center of the tendon.
  3. It does not take a lot of force to make a muscle flex. The tendon should be tap firmly but not with enough force to cause pain. The goal should be to tap the tendon with the least amount of force possible while still eliciting a reflex. This can take some practice to get right.
    • If you have a weighted hammer, it is designed to create sufficient force when it is dropped from a distance of 10 to 12 centimetres (3.9 to 4.7 in). You do not want to add additional force. Gravity will do the work. [4]
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Part 3
Part 3 of 3:

Assessing the Reflexes

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  1. With a normal reflex, the muscle will contract quickly after the connected tendon is stimulated. This response isn't necessarily immediate, but should occur within 1 second of being stimulated. [5]
  2. Hyperreflexia is a condition in which a muscle repeatedly contracts when it is stimulated. This repeated contraction will be visible once the muscle is stimulated. [6]
    • This condition usually indicates a malfunction in communication in the spinal cord.
  3. In order to ensure that you tap the tendon correctly but no response occurred, you should do it several times. With repeated reflex tests you can ensure that your test results are correct and not due to an error in your method of testing.
    • Having no response to tendon stimulation is called hyporeflexia. [7]
  4. When testing reflexes, it can help you gauge the response by comparing the same muscle on the opposite side of the body. For example, test the reflexes on 1 ankle and then immediately test the reflexes on the other ankle. Comparing the responses can allow you to spot abnormal responses. [8]
  5. In order judge how good reflexes are, most doctors grade them on a scale from 0 to 4. These numbered grades can also be given a plus or minus to indicate additional levels of response. The numerical grades correspond to responses in this way: [9]
    • 0 is no response
    • 1 is a slight response
    • 2 is a normal, quick response
    • 3 is a very brisk response
    • 4 is an abnormal repeating reflex
  6. Doctors use your grade of reflexes to verify whether your nerves are working effectively. If the muscle reacts correctly, the nerves in the muscle are communicating with the brain as they should. If the muscle doesn't react well, then there is an issue in the nerves between the muscle and the brain. This problem could be caused by a variety of issues, so your doctor will continue with addition medical tests to find the source of the problem. [10]
    • Some medical conditions that can cause poor muscle reflexes include multiple sclerosis, diabetes, alcoholism, amyloidosis, uremia, vitamin deficiencies, toxin poisoning, and certain cancers. [11]
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      Article Summary X

      To test someone’s reflexes, first get a reflex hammer, which has a rubber head to avoid causing injury. Then, locate the tendon you want to test, which will feel like a thin strip of muscle on the knee or ankle. When you’re ready to do the test, hold the hammer lightly and gently tap the tendon in 1 swift stroke. If the reflexes of the person you’re testing are normal, watch for the muscle to contract rapidly after you tap the tendon. Alternatively, the muscle may contract repeatedly, possibly indicating a communication problem in the person’s spinal cord. If you get no response, try tapping the tendon again to make sure you didn’t miss it first time around. For tips on how to compare reflexes between 2 muscles, keep reading!

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