The patellar reflex (knee jerk) is an example of the<unk>  and it is used to determine the sensitivity of the<unk> . Reflexes can be tested as part of a neurological examination, often if there is an injury to the central nervous system. To test the reflex, the muscle should be in a neutral position. The muscle being tested needs to be flexed for the clinician to locate the tendon. After the muscle is relaxed, the clinician strikes the tendon. The response should be contraction of the muscle. If this is the knee jerk reflex, the clinician should observe a kick. The clinician rates the response. + Grading of<unk> es upon tapping muscle tendon Grade Response Significance 0 no response always abnormal 1+ slight but definitely present response may or may not be normal 2+ brisk physiologic response normal 3+ very brisk response may or may not be normal 4+ clonus always abnormal The clasp-knife response is a<unk>  with a rapid decrease in resistance when attempting to flex a joint. It is one of the characteristic responses of an upper motor neuron lesion.
Stretch reflex
Tonic vibration reflex
Triceps reflex
Tendon reflex
Biceps reflex
Scratch reflex
Red reflex
Jaw jerk reflex