Ossification of the petrosphenoidal ligament: unusual variation with the potential for abducens nerve entrapment in Dorello's canal at the skull base.

Variable bony anatomy at the skull base may result in compression or entrapment of exiting cranial nerves. The authors present an unusual variation of bilateral ossification of the roof of Dorello's canal and review the germane literature. Clinicians might consider ossification of the petrosphenoidal ligament (also called Gruber's ligament) in patients with unexplained cases of abducens nerve palsy.