Morphometric Analysis of Petrous Bone With Emphasis on Landmarks Utilized in Lateral Skull Base Approaches

Background The petrous part of the temporal bone plays a crucial role in various cranial surgical approaches, particularly those involving the middle cranial fossa. Understanding the morphometry of this region is essential for minimizing intraoperative risks and enhancing surgical outcomes. This study aims to provide a detailed morphometric analysis of the petrous bone and its anatomical landmarks in an Indian population, addressing a gap in the literature. Methods The study was conducted in the Department of Anatomy and Forensic Medicine and Toxicology and involved 100 heads of unclaimed adult bodies that underwent post-mortem examination. Detailed morphometric measurements were taken using ImageJ software (National Institutes of Health, Bethesda, MD), focusing on landmarks critical for surgical approaches: the width of the trigeminal ganglion (TG), distances from the medial surface of the posterior root of the zygoma to TG (A), the lateral end of the petrous ridge to TG (B), the arcuate eminence to TG (C), the facial nerve hiatus to TG (D), the foramen spinosum to TG (E), the foramen ovale to TG (F), the superior margin of the internal acoustic meatus to the petrous ridge (G), the lateral end of the petrous ridge to the hiatus for the greater superficial petrosal nerve (GSPN) (H), the foramen spinosum to the foramen ovale (I), and the foramen spinosum to the lateral wall of the middle cranial fossa (J). Data were statistically analyzed using paired sample t-tests and Wilcoxon rank-sum tests. Results Significant differences were observed between the left and right sides for several measurements. The width of the TG averaged 13.57 ± 1.53 mm on the left and 14.20 ± 2.09 mm on the right (p = 0.029). Distances from the medial surface of the posterior root of the zygoma to TG (A) were 33.30 ± 6.26 mm (left) and 33.40 ± 5.52 mm (right) (p = 0.001). The lateral end of the petrous ridge to TG (B) measured 37.90 ± 5.72 mm (left) and 40.30 ± 3.35 mm (right) (p = 0.000). Other significant differences included distances from the arcuate eminence to TG (C), which were 28.50 ± 4.20 mm on the left and 29.60 ± 4.31 mm on the right (p = 0.001); the hiatus for the GSPN to TG (D), which were 11.00 ± 1.00 mm on the left and 10.70 ± 0.81 mm on the right (p = 0.003); and the foramen spinosum to TG (E), which were 12.60 ± 2.24 mm on the left and 11.60 ± 1.92 mm on the right (p = 0.001). Conclusion In summary, this study presents an in-depth morphometric analysis of important landmarks in the petrous bone, revealing notable differences between the left and right sides. These results emphasize the crucial variability that should be considered when planning surgeries involving the middle and posterior cranial fossa.