CLAVUS, in Medicine and Surgery, is used in several significations: 1. Clavus hystericus, is a shooting pain in the head, between the pericranium and cranium, which affects such as have the green sickness. 2. Clavus oculorum, according to Celsus, is a callous tubercle on the white of the eye, taking its denomination from its figure. 3. Clavus imports indurated tubercles of the uterus. 4. It also imports a chirurgical instrument of gold, mentioned by Amatus Lusitanus, designed to be introduced into an exulcerated palate, for the better articulation of the voice. And, 5. It signifies a callus, or corn on the foot.