An apparatus for controlled stretch of human jaw-closing muscles.

The design of a special-purpose muscle stretcher for reflex studies of the human jaw-closing muscles is described. The device is based on a servo-controlled electromagnetic vibrator which imposes controlled displacements on the lower jaw. The mechanics of the device keep jaw movements coaxial with the temporomandibular joint during the stretches. The design incorporates important safety features including mechanical stops and electronic cut-outs to protect the jaws from excessive stretches.