Macroscopic and ultrastructural findings in some diseases of the facial nerve

[Bilateral facial paralysis and diabetes: report of a case]

The author presents the case of a 68-year-old white woman who presented bilateral facial paralysis in the course of an undiagnosed diabetes mellitus. The paralysis remained stable for four years and as soon as the diabetes was treated, her symptoms improved.

[Neuroanatomy of the optic, trigeminal, facial, glossopharyngeal, vagus, accessory and hypoglossal nerves (author's transl)]

1. The intracranial and intraorbital course of the optic nerve is described concisely, the intracanicular one in full details. Apart from the wide and small sections of the optic canal, its axis opposite to the cranial planes, the coating of the canal and the adjacency to the paranasal sinuses and arteries are exactly described. 2. At the trigeminal nerve the trigeminal ganglion, its roots and also the mandibular nerve have great importance in the practical medicine considering thermo-coagulation or surgery of the trigeminal nerve. This segments and also the adjacency of the fifth nerve to the internal carotid artery and subarachinoid brain vessels are exactly, the nuclei areas and central tracts are briefly explained. 3. The nuclei of the facial nerve the intracerebral and intracisternal course and its development, the facial canal and its narrow passes are described. Also the position of the internal acoustic pore in the skull, the dimensions of the internal acoustic meatus and the relations between nerves and vessels are explained. In addition to the geniculate ganglion and the chorda tympani the communications of the facial nerve inside the temporal bone, the tympanic intumescentia (ganglion) and the nervus intermedius, also the petrosal nerves are included in the description. The sheaths of the segments of the seventh cranial nerve and also the fasciculation are exactly, the somatotopic organization is briefly described. 4. The extracranial course of the glossopharyngeal nerve is briefly, its intracranial sections are included exactly in the investigation. 5. The nuclei of the vagus nerve and the intra- und extracranial course are described. 6. The accessory nerve, its nucleus and the intra- and extracranial course are concisely explained. 7. The hypoglossal nerve, its nucleus, the emergence of the fibres and also the relations of nerves and vessels in the posterior cranial fossa are described. The hypoglossal canal and also the extracranial course are explained as briefly as possible.

Degeneration and regeneration processes in experimental facial nerve paralysis

Facial nerve paralysis was provoked by compression of its extratemporal portion in rabbits and the degeneration and regeneration of the nerve fibres was studied ultrastructurally. The compression was removed to study the regenerative process in one group of animals. Axonal and myelin degeneration were the first events seen as a collagen tissue proliferation from the endoneurium and perineurium. Ultimately all the nerve was transformed into fibrous tissue. The myelin was disintegrated by Schwann's cells without any macrophagic activity. The regeneration process begins by the axons, that are orientated towards Büngner's bands of remnants of the Schwann's cells, in which a new myelin sheath appears. Schwann's cells play an important role, in both the degeneration and the regeneration process. The final aspect of the regenerated fibres is similar to normal but they contain more collagen tissue, thinner myelin sheaths, and a greater proportion of unmyelinated fibres.