We introduce a new method of analysis of the normal and abnormal behavior of the TMJ, using a duplex-doppler spectral analysis. The method consists in monitoring the joint movement by means of a study of the Fourier transformed signals, which give information on the velocity distribution of the condylo-meniscal complex during the opening and closing phases of the jaw. Using repeated sampling over short time intervals we get a detailed description of the motion which allows to discriminate the normal and abnormal action of the condylomeniscal complex. We are able to identify various physiopathological conditions, among which opening and/or closing clicks, complex locking conditions and anomalies related to an asymmetrical behavior during the operation cycle. Duplex-doppler spectral analysis is correlated to a clinical examination in order to define various classes of anomalies.