Post-haemorrhagic subarachnoid fibrosis in dogs. Scanning electron microscopic observation and dye perfusion study.

Scanning electron microscopic observations of the subarachnoid space were made in dogs focussing upon the fibre components in both the normal subarachnoid space and in areas of post-haemorrhagic fibrosis. It was concluded that the fibrous tissue originates from the arachnoid membrane itself, while organized haematoma is considered to form a component of the fibrosis. Perfusion of the subarachnoid space of dogs with a solution of 0.1% Toluidine Blue was also done. This showed that cerebrospinal fluid (CSF) is carried from the subarachnoid space directly to the dural sinuses through a fine string-like structure, which is conceivably one of the collateral CSF absorptive pathways.