Skull thickness and halo-pin placement in children: the effects of race, gender, and laterality.

To study the effects of gender, race, and laterality on skull thickness, we reviewed 41 pairs of head computed tomography (CT) scans, matched for age and sex by race. Thickness was measured at the standard locations for halo pins (anterolateral [AL] and posterolateral [PL]) using bone windows. The average measurements ( +/- 1 SD) were right AL = 2.9 +/- 1.0, left AL = 2.8 +/- 1.0, right PL = 3.2 +/- 1.2, and left PL = 3.6 +/- 1.2 mm (range, 1.2-7.2). There were no statistically significant differences by race or gender. The average thickness increased with age. There was a difference between the right and left PL sites (3.2 +/- 1.1 vs. 3.6 +/- 1.2 mm) but not between the AL sites. Caution in halo application must be applied equally to all children.