Aditus ad Antrum on Normal Temporal Bone CT Scan.

INTRODUCTION

The aditus ad antrum is a structure located on the posterior wall of the tympanic cavity, connecting the epitympanum and mastoid antrum, playing a role in ventilating the mastoid antrum and air cells. However, there is limited in-depth research on this structure.

OBJECTIVE

To study the anatomy and morphology of the aditus ad antrum and evaluate its correlation with mastoid pneumatization using 3D MPR-reconstructed CT scans.

METHODS

This cross-sectional descriptive study was conducted using 101 normal temporal bone CT scans (190 ears) from individuals aged 16 years or older in Vietnam. The aditus was examined in three planes (axial, coronal, and sagittal) using 3D MPR reconstruction.

RESULTS

The aditus ad antrum morphology was classified into four groups, with group 2 being the most prevalent (48.42%). There was no correlation between aditus morphology and gender or ear side. Additionally, no relationship was found between mastoid pneumatization and aditus morphology. With increasing mastoid pneumatization, aditus ad antrum dimensions change. In individuals with two normal ears ( N  = 89), bilateral symmetry in aditus morphology was observed in 45% of cases. No significant differences were found in aditus dimensions between ears. The mean transverse diameter of the aditus in males was significantly larger than in females ( p  < 0.05). The anterior-posterior diameter of the right ear was significantly greater than the left in the same individual ( p  < 0.05).

CONCLUSION

The aditus ad antrum may differ between the left and right ears in normal individuals and is not associated with mastoid pneumatization.