The mesencephalic nucleus of the trigeminal nerve was the target of extensive investigations using anatomical and physiological techniques. The nucleus has been regarded as a proprioceptive centre for the muscles of mastication in addition to some other cranrlal muscles. A number of authors claimed that a connection existed between the esencephalic
nucleus and the oculomotor nerve (Woollard, 19Bl and Tarkhan, 1934), the trochlear ancl adbtrcent nerves (Vedral, 1g68) as well as the hypoglossal nerve (Stephens and Smith, 1969). The mesencephalic nucleus has been described
by Cajal (1909) to be composed of an inferior part ( head ) and a superior narrower part ( tail ) rvhose cells are smaller in size than those of the head.