A Morphometric Study of the Internal Acoustic Meatus in Dry Skulls

The internal auditory canal extends from the porous acusticus medially to the fundus laterally. At the fundus, a vertical bony plate formed by the falciform crest separates the canal from the inner ear and divides it into compartments. Owing to its role as a conduit for vital neurovascular structures, the internal acoustic meatus (IAM) is clinically important in otologic and neurosurgical procedures.

To evaluate the morphometry of the IAM and provide reference data for neurosurgeons and otologists.

This descriptive cross-sectional study was conducted on 72 temporal bones (36 right and 36 left) obtained from the department of anatomy of a tertiary care teaching hospital.

Seventy-two dried adult human temporal bones were studied. A silicone material was injected into the internal acoustic meatus to obtain the impressions for morphometric assessment.

Mean values were calculated. Side comparisons were performed using the independent samples t-test, and Pearson's correlation coefficient assessed right-left relationships.

The mean width of the porus acusticus was 3.60 ± 0.54 mm on the right and 3.74 ± 0.42 mm on the left. The mean height measured 4.27 ± 0.69 mm on the right and 4.53 ± 0.60 mm on the left. No statistically significant difference was found between the sides. Pearson's correlation showed a weak, negative, and statistically nonsignificant correlation.

The findings indicate a relative bilateral symmetry of the porus acusticus, providing baseline morphometric data useful for surgical planning and minimizing neurovascular injury during procedures involving the IAM.