In FVOO, cerebrospinal fluid (CSF) is blocked at the fourth ventricle outlets by a membranous structure in the absence of any additional obstructive organic pathologies. Various terms for referring to FVOO have been used in previous reports, such as fourth ventricle/ventricular outlet obstruction 1) 2) 3) , fourth ventricular outflow obstruction , membranous obstruction of the fourth ventricle outlet 6) , obstruction of Magendie’s and Luschka’s foramina 7) , obstruction of fourth ventricular exit 8) and primary obstruction of the fourth ventricle outlets . Far distal obstructive hydrocephalus is a term that includes Dandy Walker or Arnold Chiari malformation, membranous obstruction or fourth ventricle and intercisternal external obstruction of the CSF .