Osteology of the Skull as It Affects Halo Pin PlacementGARFIN, STEVEN R., MD*; BOTTE, MICHAEL J., MD*,‡; CENTENO, RICARDO S., MD†; NICKEL, VERNON L., MD*,‡Spine: October 1985 - Volume 10 - Issue 8 - p 696-698 Original Article: PDF Only Buy Abstract Author InformationAuthors Twenty-seven cadaver skulls and 20 CT scans of skulls were measured above the orbital rim and ear but below the greatest diameter to determine optimal placement of halo pin sites. At the antero- and posterolateral portions of the calvaria, the outer table averaged 2 mm, the diploe 3 mm, and the inner table 2 mm. At the temporal fossa, the outer cortex averaged 1.7 mm, the diploe 2.0 mm, and the inner table 1.6 mm. Average distance between the anterior edge of the temporal fossa and the frontal sinus approximated 3 cm. These data confirm previously recommended halo pin insertion sites, anterolaterally and posterolaterally, where the bone is thickest and the thinner frontal sinus and temporal fossae are avoided. *From the Division of Orthopaedics and Rehabilitation, University of California, San Diego, California †From the Department of Radiology, University of California, San Diego, California ‡From the Donald M. Sharp Rehabilitation Hospital, San Diego, California © Lippincott-Raven Publishers.