Reflexes in response to stretch (myotatic reflexes)

Abstract Familiar to those who work with the decerebrate preparation must be the observation that passive flexion of the characteristically extended knee is felt to evoke some development of resistance of it against that passive movement. Examination by the myograph of this resistance formed the point of departure of the following observations. In this same muscle the “knee jerk” is doubtless a reflex in response to a stretch; but it is a reaction whose brevity makes it perhaps the most twitch-like of all reflexes, whereas the reflex under consideration here is tetanic and prolonged. Patellar-clonus, likewise a reaction to stretch, resembles a spaced series of knee jerks and, wanting tetanic character, likewise differs from the reflex under consideration here.