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 causes no patellar...
MMG, mechanomyography; EMG, electromyography; RMS, root mean square; MPF, mean power frequency. Full size image Figure 6 Typical MMG waveform. The patellar tendon reflex's typical raw waveform with hyperreflexia (a) and control (b). After 2–100 Hz bandpass filtering of hyperreflexia (c) ...