A CT Study to examine Morphometry and anatomical Variations of Foramen Ovale

Introduction The foramen ovale (FO) is located in the greater wing of sphenoid, posterolateral to foramen rotundum and transmits the mandibular nerve. Other structures passing through it are accessory middle meningeal artery, lesser petrosal nerve and emissary veins. A comprehensive knowledge of the anatomy of this area is crucial for accurate interpretation and delineation of pathology. Aim and Objectives 1. To study the anatomic variations of foramen ovale. 2. To record and analyze the metric and non metric data of foramen ovale. Material & Method Type of Study Retrospective observational. Sample size 200 Computerized tomography (CT) head axial section scans with no evidence of disease that might alter foraminal anatomy, from picture archiving & communication system (PACS). The Computer-assisted measurements of foraminal parameters were obtained on both right and left sides. Statistical tests applied unpaired t-test, paired t-test, ANOVA. Result Foramen ovale of 110 males, 90 females were examined. Shapes oval (84%), almond (12.5%), round (1%), slit- like (2%) and irregular (0.5%).In 0.5%, it was open postero-medially. In rest of the cases, it was closed on all sides. Septation observed in 2% cases. Morphometry The mean length, breadth, distance from mid-sagittal plane & size in males were 7.75± 1.16, 3.98±0.91,21.40±1.75 & 30.94±8.79, and in females, measurements were 6.90±0.78, 3.57±1.04,20.36±1.62 & 24.86 ± 9.08 respectively. The mean area in males is 30.22 mm2 (R) and 31.72 mm2 (L) and in females it is 24.00 mm2 (R) and 22.90 mm2 (L). Conclusion Significant difference is seen between males and females, and right and left side in all four parameters. Variations in the shapes of the FO are found due to developmental reasons, which may affect clinical and diagnostic procedures. While undergoing invasive procedures like microvascular decompression by percutaneous biopsy of cavernous sinus tumors, or for a CT guided transfacial fine needle aspiration technique through the FO, a thorough knowledge of the normal anatomy of the foramen ovale and variations may help in diagnosis and management of neuralgia, nerve compression diseases and for novel microsurgical techniques.