Radiological assessment of the fossa of Rosenmüller using cone-beam computed tomography: A retrospective study

The fossa of Rosenmüller (RF) is a herniation of nasopharyngeal mucosa through a defect between the skull base and the superior-most fibers of the superior constrictor muscle. Its anatomy and relationships help explain symptoms commonly seen in nasopharyngeal disorders, as well as potential pathways for direct disease extension. This retrospective study aims to assess RF anatomy using two- and three-dimensional measurements and to evaluate these findings according to demographic parameters.

To assess the anatomy of RF via two- and three-dimensional measurements and evaluate the findings according to demographic parameters.

Cone-beam computed tomography images from 500 Turkish patients were retrospectively assessed by two observers, each performing measurements twice. Images were acquired using a Planmeca Promax 3D Max system (Planmeca, Helsinki, Finland) (70-90 kVp; 9-10 mA; exposure time 10-15 seconds). Measurements included RF depth, width, angle, and volume. Patient age and sex were recorded. Volume measurements were performed using 3D Doctor software (Able Software Corp., Lexington, United States). The Mann-Whitney U test was used to assess differences between groups. Intraclass correlation coefficients were calculated to evaluate intra- and inter-observer agreement. Statistical significance was set at P < 0.05.

The mean width was 4.21 ± 1.43 mm (median: 4.16; range: 1.17-11.09), and the mean depth was 12.82 ± 3.39 mm (median: 12.84; range: 4.79-25.86). The mean angle relative to the sagittal plane was 52.34° ± 9.11° (median: 51.40; range: 9.28-79.90). Volumetric analysis demonstrated a mean RF volume of 334.78 ± 329.93 mm³ (median: 210.67; range: 29.31-1632.76), indicating substantial interindividual variability. No statistically significant sex-related differences were identified in width (female: 4.20 ± 1.46 mm; male: 4.24 ± 1.41 mm; P = 0.885), depth (female: 12.82 ± 3.39 mm; male: 12.80 ± 3.44 mm; P = 0.973), or angle (female: 51.66° ± 9.75°; male: 53.52° ± 7.88°; P = 0.296). Similarly, volumetric measurements did not differ significantly between females and males (307.26 ± 304.78 mm³ vs 383.26 ± 368.99 mm³, respectively; P = 0.336). Intraclass correlation coefficients demonstrated excellent intra- and inter-observer agreement for all measurements (P < 0.001).

Cone-beam computed tomography may provide useful information for assessing the RF.