Objective:To measure the length and curvature of the external auditory canal (EAC) centerline using a three-dimensional (3D) measurement method based on high-resolution computed tomography (HRCT).Methods:A retrospective analysis was conducted on HRCT images of healthy EAC from 49 patients (64 ears) examined at the Sixth Medical Center of the PLA General Hospital from June to October 2024. The cohort included 25 males (28 ears) and 24 females (36 ears), aged 22-78 years (mean age 47.3 years), categorized into age groups: 18-30 years (20 ears), 31-60 years (22 ears), and 61-80 years (22 ears). The EAC comprised 29 left and 35 right ears. 3D reconstruction of the EAC was performed using medical software (3D Slicer), and the central curve of the EAC was extracted using an improved measurement method to determine its length and curvature. Statistical analysis was performed using Origin Pro 2023 software to compare differences across genders, sides, and age groups.Results:The measurements of EAC length and curvature revealed that the EAC was significantly longer in males than in females (27.46 mm vs. 25.44 mm, P=0.014) and longer on the right side than on the left (27.99 mm vs. 25.87 mm, P=0.031). No statistically significant difference in EAC length was observed among the different age groups ( P>0.05). Furthermore, no statistically significant differences in EAC curvature were found regarding gender, side, or age group (all P>0.05). Conclusion:The HRCT-based 3D reconstruction technique enables the establishment of a rapid and effective automated workflow for extracting the central curve of the EAC and systematically measuring its length and curvature. The data obtained provide a reference and methodological support for further research on anatomical variations of the human EAC and its potential clinical applications, such as the design of otological instruments or surgical planning.

Objective:To measure the length and curvature of the external auditory canal (EAC) centerline using a three-dimensional (3D) measurement method based on high-resolution computed tomography (HRCT).Methods:A retrospective analysis was conducted on HRCT images of healthy EAC from 49 patients (64 ears) examined at the Sixth Medical Center of the PLA General Hospital from June to October 2024. The cohort included 25 males (28 ears) and 24 females (36 ears), aged 22-78 years (mean age 47.3 years), categorized into age groups: 18-30 years (20 ears), 31-60 years (22 ears), and 61-80 years (22 ears). The EAC comprised 29 left and 35 right ears. 3D reconstruction of the EAC was performed using medical software (3D Slicer), and the central curve of the EAC was extracted using an improved measurement method to determine its length and curvature. Statistical analysis was performed using Origin Pro 2023 software to compare differences across genders, sides, and age groups.Results:The measurements of EAC length and curvature revealed that the EAC was significantly longer in males than in females (27.46 mm vs. 25.44 mm, P=0.014) and longer on the right side than on the left (27.99 mm vs. 25.87 mm, P=0.031). No statistically significant difference in EAC length was observed among the different age groups ( P>0.05). Furthermore, no statistically significant differences in EAC curvature were found regarding gender, side, or age group (all P>0.05). Conclusion:The HRCT-based 3D reconstruction technique enables the establishment of a rapid and effective automated workflow for extracting the central curve of the EAC and systematically measuring its length and curvature. The data obtained provide a reference and methodological support for further research on anatomical variations of the human EAC and its potential clinical applications, such as the design of otological instruments or surgical planning.