Fig. 3

Midsagittal reconstructed images of computed tomography scan of the posterior fossa and the craniovertebral junction demonstrating the various angular craniometric parameters. a Basal angle; angle between line connecting the nasion to the tip of the dorsum sellae and line extending from the tip of the dorsum sellae to the tangential surface of clivus, b Boograd’s angle; Angle between line connecting the tip of the dorsum sellae to the basion and line from the basion to the opisthion, c Nasion–Basion-Opisthion;Angle between line connecting nasion, basion and opisthion, d Foramen magnum angle; Angle between Chamberlain’s line and McRae’s line, e Clivus canal angle; Angle between the line connecting the tip of the dorsum sellae to the basion extrapolating inferiorly and line between the inferodorsal portions of the axis to the most superodorsal part of the odontoid process extrapolating superiorly f Clivopalatal angle; Angle between lines connecting the tip of the dorsum sellae to the basion and the basion to the posterior pole of the hard palate, g Clivoodontoid angle; Angle formed at the intersection of a line connecting tip of dorsum sellae to basion extrapolating inferiorly and the one along the long axis of the odontoid process, h Clivo-Supraocciput angle; Angle formed between intersection of inferiorly extrapolated lines connecting the tip of the dorsum sellae to the basion and IOP to the opisthion i Tentorial slope; Angle between line along the tentorium to IOP and IOP-O line, j Tentorial twinning line angle; Angle between line along the tentorium to IOP and the twinning line