Metrical and non-metrical study of anterior clinoid process in South Indian adult skulls

Background: The complex architecture of the anterior clinoid process (ACP), which is usually removed during the surgical elimination of tumors or aneurysms of sellar region, has surgical importance. For effective clinoidectomy, a neurosurgeon must have the prior knowledge of anatmoical variations of ACP. The purpose of this study was to investigate the dimensions and variation in the shape of ACP in dry adult skulls of South Indian origin. Methods: The study was conducted on 25 dry adult South Indian skulls of either sex. Basal width, length and thickness of ACP were measured on both the sides using Vernier caliper. Non-metrical parameters such as shape, direction of ACP were recorded. Results: ACP exhibited different anatomical variations with respect to their shape and direction. Triangular, pentagonal, nipple shaped, J-shaped and finger like ACP's were observed in these skulls. Bilaterally triangular ACP was the most common type observed (64%). ACP was bilaterally straight in 68% of the skulls and bilaterally curved in 16% of the skulls. ACP with blunt end and pointed end was observed bilaterally in 52 and 24% of the skulls, respectively. The average length, basal width and thickness of ACP on right side was 10.68 ± 1.90, 12.4 ± 2.58 and 6.88 ± 1.09 mm, respectively, and on the left side it was 9.96 ± 1.71, 11.12 ± 1.81 and 6.52 ± 0.96 mm, respectively. Conclusions: The result of the present investigation suggests that ACPs of South Indian skulls are highly variable and, are marginally larger and thicker than ACPs of Nepalese and Korean origin.