[An electrophysiological study on the mechanoreceptor of canine knee joints]

Passive extending and flexing and change in intraarticular pressure were applied to canine knee joints and nerve impulses from the posterior articular nerve, an articular branch of the tibial nerve, were studied. On extending and flexing the knee, in the intermediate position the nerve impulses were of low frequency but on excessive extension high frequency nerve impulses were observed. The relationship between the angle of the joint and the frequency of nerve impulses exhibited a hysteresis phenomenon. On changing the intraarticular pressure, the frequency of nerve impulses increased with an increases in pressure and it depended directly on the intraarticular pressure. The mechanoreceptors of joints probably play a warning function for the protection of the joint by effectively informing the extreme conditions and non-physiological conditions to the central nervous system.