To view comprehensively the disturbances or sensation, as expressed in the neuralgias of the face, one must bear in mind three possible sources of sensory supply, the trigeminal nerve, the facial nerve, and possibly the sympathetic. Studied phylogenetically, we find in the lower forms of animal life a close alliance between the facial and trigeminal nerves, both as to their nuclear origin and peripheral course and distribution. Throughout the trigeminal tract there is an abundant provision for sympathetic control or association. These sympathetic connections may not be without their significance.The varieties of sensory disturbance, as seen in the neuralgias, typify different forms of sensations, including pain, pressure, and heat. In the trigeminal nerve, as in other nerves with sensory fibers there should be, as there appears to be, disassociation of sensation. A study of patients with paralysis of the trigeminal, facial and sympathetic singly and in combination has been made to allocate their different forms of sensation. The differential diagnosis between the atypical and typical neuralgias and especially major trigeminal neuralgia is essential in the decision for or against the major operation.Whatever may be the cause of major trigeminal neuralgia, infection plays no part. The pain is relieved only by two measures, alcoholic injection and section of the sensory root. The latter, or major operation is almost devoid of risk. The author has performed over 300 major operations, the last 205 with only 1 death.