Orbital osteology: a study of the surgical landmarks.

This study was conducted to re-examine the osteological anatomy of the orbit. Previous studies examined dried human skulls; this study looks at cadaveric specimens in a population that more closely resembles the population in the United States. Measurements were made of the bony orbit to define safe distances for surgical intervention and to identify distances to intraorbital fissures, canals, and foramina. Safe distances to the optic nerve were identified by subtracting 5 mm from the shortest measured specimen. The safe distances were as follows: medial quadrant, 29 mm; inferior quadrant, 39 mm; superior quadrant, 38 mm; and lateral quadrant, 36 mm. Staying close to the bony wall, not exceeding these parameters, and careful identification of anatomical structures should keep the surgeon from inadvertent damage to the intraorbital structures.