Spinal arachnoid cysts are relatively uncommon lesions that may be intradural or extradural with the intradural variety being rare.    From Wordnik.com.  [Medlogs - Recent stories] Reference

This atlas illustrates the anatomical structures of the upper basal cisterns, their topography and relationship to other intra - and extradural structures.    From Wordnik.com.  [Medical eBooks - Download Free Books] Reference

Once Aadi has been admitted to hospital, Sunita and Dev are informed that their son has suffered an extradural haemorrhage, which is putting pressure on his brain.    From Wordnik.com.  [All - Digital Spy - Entertainment and Media News] Reference