Margins of safety in lateral orbitotomy

Five adult cadaver half skulls were used to study the bone cuts of the lateral orbital wall in performing the lateral orbitotomy. Measurements were taken of the anterior vertical opening, the anteroposterior opening, and the distance to the middle cranial fossa. The vertical opening at the anterior aspect of the lateral orbital wall ranged from 18 to 22 mm. The anteroposterior exposure averaged 18 mm when the thick and thin portions of the bone were removed. The distance from the anterior rim to the middle cranial fossa averaged 31 mm on both the superior and inferior cuts. Hence a distance of approximately 12 to 13 mm separated the posterior aspect of the orbitotomy from the middle cranial fossa.