The thickness of the skull in Korean adults

New instrumentation and techniques for skeletal fixation have been developed in response to concerns regarding variability of the skull base and the calvaria. The fear of intracranial penetration has limited the use of internal or external fixation to the skull base and the calvaria. Despite potential clinical usefulness, limited anthropometric data have been reported on the skull base and the calvaria. The purpose of this study was to measure the average thickness of various points of the skull base and the calvaria of Korean adults. Fifty-one Korean adult skull bases and calvaria, which were cut 2 cm above the supraorbital margin anteriorly and 2 cm above the inion posteriorly, were measured in this study. Thickness of 13 clinically important points were measured with a Teclock GM-21 Calipergauge (Teclock Co., Tokyo, Japan). The mean thickness of the two opposite sides were compared using paired t-tests. They did not differ significantly from the others except for three points. Frontal bone A (located 1 cm above the supraorbital margin and 1.5 cm lateral to the midline) was 6.35 +/- 2.88 mm, frontal bone B (located at the midpoint of the frontal midpoint and the frontoparietal suture on the cut edge) was 5.24 +/- 1.50 mm, frontal bone C (located at the midpoint of the vertex and frontal bone B) was 6.63 +/- 1.77 mm, the pterion was 3.19 +/- 0.85 mm, the midpoint of the squamous temporal was 1.96 +/- 0.65 mm, parietal bone A (located 1.5 cm below the middle meningeal groove) was 3.99 +/- 1.11 mm; parietal bones B and C (divided at the distances between the frontoparietal suture and the occipital midpoint with a ratio of 1:3 and 2:3 respectively on the cut edge) were 4.71 +/- 1.06 mm and 5.35 +/- 0.91 mm respectively, occipital bone A (located 1.5 cm posterolateral from the foramen magnum) was 2.31 +/- 1.00 mm, occipital bone B (located 1.5 cm lateral to the midline and 0.5 cm above the inion) was 5.41 +/- 1.50 mm, occipital bone C (located occipital to the midpoint and 2 cm above the inion) was 8.2 +/- 1.67 mm, the orbital roof was 1.37 +/- 1.08 mm, and the orbital lateral wall was 2.25 +/- 1.06 mm. The data give practical information for determining the position and depth for safe and effective internal or external fixation during craniofacial procedures.