A simple myelographic maneuver for the detection of mass lesions at the foramen magnum.

Popular belief and teaching has emphasized the necessity for supine myelography to avoid missing lesions on the dorsal aspect of the foramen magnum; however, this required not only additional time but also considerable discomfort for the patient. A simple maneuver added to the prone myelogram, requiring little additional time and no discomfort, virtually assures the detection of lesions at or near the foramen magnum. This technique has been used in 40 patients suspected of having either a demyelinating process or a mass lesion involving the high cervical cord. Eight Chiari malformations and 1 meningioma were demonstrated.