THE NASAL ROUTE OF CEREBROSPINAL-FLUID DRAINAGE IN MAN - A LIGHT-MICROSCOPE STUDY

The drainage routes from the subarachnoid space to the nasal mucosa we re investigated in autopsy material. Indian ink, applied post-mortem t o the olfactory groove, promptly filled the perineurial spaces around the olfactory nerve branches in the dura, the lamina cribrosa and the submucosal tissue in the nose. In a case of recent subarachnoid haemor rhage, the perineurial spaces even around the most distal olfactory ne rve branches were congested with blood and there was an abundant accum ulation of red corpuscles in the apical part of the nasal mucosa. Iron -containing pigment was found in the perineurial spaces of proximal an d distal olfactory nerve branches as well as in the nasal mucosal stro ma in cases with older haemorrhagic lesions.-The findings show that th e perineurial spaces provide an efficient drainage route from the suba rachnoid space to the nasal mucosa in cases with haemorrhagic cerebral lesions. A complementary drainage route for the cerebrospinal fluid w as indicated by the presence of indian ink, red corpuscles and iron pi gment in arachnoid villi, which penetrated the lamina cribrosa and end ed in the nasal submucosal tissue. Iron in the deep cervical lymph nod es should not be taken as evidence of transport from the CNS, since ir on pigment was also found in cases without intracranial haemorrhage.