MORPHOMETRIC ANALYSIS AND GEOMETRIC VARIATIONS OF THE INTERNAL ACOUSTICMEATUS IN THE SOUTH INDIAN POPULATION: A CT IMAGING STUDY

Background: The internal acoustic meatus (IAM) is a bony canal located between the labyrinth and the posterior cranial fossa. Understanding its normal dimensions and morphology is essential for evaluating skull trauma, identifying congenital anomalies that may affect individual nerves, and preparing for ear surgeries. This study aims to determine the normal dimensions and morphology of the IAM using Computed Tomography(CT), creating a morphological database specific to the South Indian population. To determine the morphometry and shapes of intern Objective: al acoustic meatus in healthy south Indian population aged between 10-60 years. This study Materials And Methods: which was a retrospective study, was carried out from the 500 healthy subjects (214females;286 males) aged 10-60 years. Subjects had undergone routine CT brain in the Radiology Department. The study comprised 359 males Results: and 141 females. The average IAM measurements were as follows: for males, the length was 9.19 mm on the right and 9.25 mm on the left; the width measured 3.7 mm on the right and 3.77 mm on the left; and the height was 4.1 mm on the right and 4.06 mm on the left. For females, the corresponding measurements were 9.4 mm (right) and 9.28 mm (left) for length; 3.7 mm (right) and 3.8 mm (left) for width; and 4.1 mm (right) and 4.06 mm (left) for height. A significant difference was noted in the length of the internal acoustic meatus between males and females on the right side (p = 0.034). The other parameters did not show significant differences (p > 0.05). These measurements offer a normative Conclusion: reference for the internal acoustic meatus in the South Indian population. Understanding the normal dimensions and shapes is crucial for assessing clinical conditions and tumor processes. A narrow internal acoustic canal is associated with unilateral and bilateral congenital sensorineural hearing loss and cochlear nerve hypoplasia, while a dilated canal may indicate expansion due to an acoustic neuroma or other lesions.