Arthrokinetic reflex of the knee.

Abstract

The knee joint of decerebrate cats was rotated through a full range of flexion-extension movements. The tensions of quadriceps femoris muscle and semitendinosus muscle were recorded and the responses of these muscles to joint movement were studied. The medial and posterior articular nerves were later sectioned and control records were taken. Flexion of the knee decreased the tension of quadriceps femoris but increased that of semitendinosus. Re-extension of the knee restored both tensions to their resting values. Data were obtained which showed that these responses were reflex in nature. Since the knee joint reflex is basically a slow adapting movement reflex, the name ‘arthrokinetic reflex’ seems appropriate. The activity of the arthrokinetic reflex indicates that its general function is to coordinate knee movement with other nervous activity in thigh muscles. In addition to this, the arthrokinetic reflex of the knee appears to have specific orientation toward dealing with the powerful stretch reflex of the quadriceps femoris muscle.