Chamberlain's line

line drawn on lateral radiograms or tomograms of the skull about the craniovertebral junction joining the posterior end of the hard palate to the posterior lip of the foramen magnum. In about 50% of normal subjects the tip of the odontoid is at, or below, Chamberlain's line. If more than half of the odontoid process is above this line, basilar invagination or impression is probably present (see basilar impression).

GS