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Technique of elicitation of deeptendon reflex

In a screening examination you it more convenient to integrate the reflex examination into the rest of the examination of that part of the body; that is, do the lower extremity reflexes when examining the rest of the lower extremity. When there is an abnormality of the reflexes is noted , however, the reflexes should be examined as a group with careful attention given to the technique of the examination.
Reliable test results are best obtained when the patient is fully relaxed
Explain the procedure to the patient
  • If you fails to get any response with a specific reflex that can usually occcur with ankle jerks then try the following:
  • Several different positions of the limb.
  • Get the patient to put slight tension on the muscle being tested. One method of achieving this is to have the patient strongly contract a muscle not being tested.
  • In the upper extremity, have the patient make a fist with one hand while the opposite extremity is being tested.
  • If the reflex being tested is the knee jerk or ankle jerk, have the patient perform the "Jendrassik maneuver," a reinforcement of the reflex . The patient's fingers of each hand are hooked together so each arm can forcefully pull against the other. The split second before you are ready to tap the tendon, say "pull."
  • In general, any way to distract the patient from what you are doing will enhance the chances of obtaining the reflex. you can instruct the patient to count or give the names of children are examples.
The best position to elicit reflex is that the patient to be sitting on the side of the bed or examining table. The Babinski reflex hammer may be used..
  • Use a brisk but not painful tap. 
  • Use your wrist, not your arm, for the action. 
  • In an extremity a useful maneuver is to elicit the reflex from several different positions, rapidly shifting the limb and performing the test. Use varying force and note any variance in response.
  • After obtaining the reflex on one side, always go immediately to the opposite side for the same reflex so that you can compare them.
You should note the following features of the reflex response:
  • Amount of hammer force necessary to obtain contraction
  • Velocity of contraction
  • Strength of contraction
  • Duration of contraction
  • Duration of relaxation phase
  • Response of other muscles that were not tested. When a reflex is hyperactive, that muscle often will respond to theexamination of a nearby muscle. A good example is reflex activity of a hyperactive biceps or finger reflex when the brachioradialis tendon is tapped. It is termed "overflowing" of a reflex.