Fenestrated capillaries in subarachnoid space in the caudal spinal cord of the premature rat: an electron microscopic observation

Abstract The fine structure of the corms medullaris of the spinal cord and surrounding structures were studied in postnatal developing rats, with special attention being paid to the vasculature. The most striking finding was the presence of fenestrae in the capillary endothelium of the subarachnoid space. These structures were not obvious in adult rats. The fenestrated capillaries may influence fluid dynamics in the subarachnoid space of the spinal cord at the level of the conus medullaris, during early stage of postnatal development.