Table 5.

Morphometric comparison table

Study	Population	Method	Vertical/ Longitudinal (mm)	Transverse/ Width (mm)	Mean Area (mm2)	Key Findings
Acar et al. [1]	Turkey	CT (256-slice)	N/A	3.57 ± 0.74 (Avg)	N/A	FR-Midline distance: 17.51 mm.
Bhattarai et al. [6]	Nepal	CT (Coronal)	2.41 ± 0.49 (H)	2.40 ± 0.55 (W)	4.58 ± 1.49	No significant sex-based difference or side-to-side asymmetry.
Ganesh et al. [10]	India	CT (1 mm)	N/A	N/A	N/A	Measured FR distance to midline (Avg: 18.27 mm).
Kastamoni et al. [15]	Turkey	CT (3D)	2.14 ± 0.47 (L)	2.05 ± 0.48 (W)	3.47 ± 1.59	Asymptomatic group; dimensions significantly smaller in TN patients.
Kastamoni et al. [15]	Turkey	CT (3D)	1.78 ± 0.42 (L)	1.77 ± 0.46 (W)	2.86 ± 1.44	TN Group (Painful side); statistically narrower than asymptomatic group.
Karthikeyan et al. [14]	India	Dry Skull	4.01 ± 0.7 (Lg)	3.74 ± 0.6 (T)	N/A	Right side; distance to midline 16.67 mm.
Karthikeyan et al. [14]	India	Dry Skull	4.56 ± 0.8 (Lg)	3.96 ± 0.9 (T)	N/A	Left side; distance to midline 18.53 mm.
Erbagci et al. [9]	Turkey	CT (Coronal)	3.04 × 3.2 (Avg)	N/A	N/A	TN Group; dimensions highly symmetrical.
Erbagci et al. [9]	Turkey	CT (Coronal)	2.4 × 3.2 (Avg)	N/A	N/A	Control Group; no significant difference from TN patients.
Berlis et al. [5]	Germany	Direct (Skull)	3.09 ± 0.69 (H)	3.29 ± 0.63 (B)	N/A	Direct anatomical measurements of 60 macerated skulls.
Berlis et al. [5]	Germany	CT (Coronal)	3.13 ± 0.56 (H)	3.11 ± 0.78 (B)	N/A	Found good correlation (r = 0.61–0.69) for FR in coronal planes.
Ginsberg et al. [11]	USA	CT (Axial)	3.55 (Avg)	N/A	N/A	Identified accessory canals (Inferior & Lateral Rotundal Canals).
Unver Dogan et al. [24]	Turkey	Dry Skull	3.11 (L)	3.11 (W)	N/A	Reported FR as consistently symmetrical in most individuals.

(H) = Height; (Lg) = Longitudinal; (L) = Length; (W) = Width; (B) = Breadth; (T) = Transverse. TN: trigeminal neuralgia