title: Os odontoideum with "free-floating" atlantal arch causing C1-2 anterolisthesis and retrolisthesis with cervicomedullary compression.
authors.affiliation: Department of Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow - 226 014, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Behari
authors.forename: Awadhesh
authors.initials: A
authors.lastname: Jaiswal
authors.forename: Arun
authors.initials: A
authors.lastname: Srivastava
authors.forename: Dinesh
authors.initials: D
authors.lastname: Rajput
authors.forename: Vijendra K
authors.initials: VK
authors.lastname: Jain