From: Grisel’s syndrome: a case report on this rare pediatric disease and its anesthetic challenges
Type I | The atlas is rotated on the odontoid, and there is no anterior displacement of the atlas |
Type II | The atlas is rotated on one lateral articular process with 3 to 5 mm of anterior atlas displacement |
Type III | Rotation of the atlas with an anterior displacement greater than 5 mm |
Type IV | Rotation and posterior displacement of the atlas |