Hydraulicspinalcordandcaudaequinanerveinjuriesareveryuncommon.Since1996,wehavereceivedandtreated4patientswithhydraulicspinalcordandcaudaequinainjuries.Thisreportgivesadetaildescription.Fourpatientswithhydraulicspinalcordandcaudaequinanerveinjuries,male:3,female:1,aging13-56yearshavebeentreatedinourhospitalsince1996.Extraduralblockinginjurywasin1patient,extraduralanaesthesiainjuryin1patientandintraspinalcanalmyelographyinjuryin2patients;thesegmentsofintraspinalcanalwereL2-3andL3-4.Onepatientwasaccompaniedbyfemoralfracture,2patientsbyintraspinaltumorand1patienthadoperationbecauseofprolapseoflumbarintervertebraldisc.