Skull Base 2011; 21(6): 373-378
DOI: 10.1055/s-0031-1287678

© Thieme Medical Publishers

Qualitative and Quantitative Radio-Anatomical Variation of the Posterior Clinoid Process

Asem Salma1 , Nishanta B. Baidya1 , Benjamin Wendt1 , Francisco Aguila2 , Steffen Sammet2 , Mario Ammirati1
  • 1Department of Neurological Surgery, Ohio State University Medical Center, Columbus, Ohio
  • 2Department of Radiology, Ohio State University Medical Center, Columbus, Ohio
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27. September 2011 (online)


This study was conducted to investigate the radiological anatomy of the posterior clinoid process (PCP) to highlight preoperative awareness of its variations and its relationships to other skull base landmarks. The PCPs of 36, three-dimensional computed tomographic cadaveric heads were evaluated by studying the gross anatomy of the PCP and by measuring the distances between the PCP and other skull base anatomical landmarks relevant to transnasal or transcranial skull base approaches. PCP variations were found in five specimens (14%): in two the dorsum sellae was absent, in one the PCP and the anterior clinoid process (ACP) were connected unilaterally and in two bilaterally. The mean distance between the right/left PCP and the crista galli was 45.14 ± 4.0 standard deviation (SD_/46.24 ± 4.5 SD, respectively, while the distance to the middle point of the basion at the level of the foramen magnum was 40.41 ± 5.1 SD/41.0 ± 5.2 SD, respectively. The mean distance between the PCP and the ACP was 12.03 ± 3.18 SD on the right side and 12.11 ± 2.77 SD on the left. The data provided highlights the importance of careful preoperative evaluation of the PCP and of its relationships to other commonly encountered skull base landmarks. This information may give an idea of the exposure achievable through different transcranial and transnasal approaches. This is especially relevant when neuronavigation is not available.


Mario AmmiratiM.D. M.B.A. 

Department of Neurological Surgery, N1025 Doan Hall

410 W. 10th Avenue, Columbus, OH 43210