No special field of surgery dealing with the cranial nerves exists today. This is not surprising in view of the characteristics of this group of morphologically and topo graphically heterogenous nerves. Morphologically we must differentiate between central nerves (I, II and VIII) and the so-called peripheral nerves (nn. III to VII and IX to XII), in which post-lesion rgeneration is quite different. Anatomo-topographi cally we must consider an intracranial and an extracranial part of each cranial nerve. For practical reasons at operation, further subdivisions of the intracranial course of...