Sphenoid Ridge in Fetuses: Size Analysis, Classification, and Clinical Implications.

Objective: To identify the size and angle of the sphenoid ridge (SR) in fetuses.

Methods: Skull bases of 32 fetuses (11 males / 21 females) aged 17 to 32 weeks of gestations were included the study. The angle of SR (SRA), length of LW (SRL), and also LW widths at the midline (SRW-ML), at the midpoint (SRW-MP), and at the lateral point (SRW-L) were measured.

Results: SRL, SRA, SRW-ML, SRW-MP, and SRW-L were measured as 22.98±4.62 mm, 150.69±8.05 degrees, 6.57±1.46 mm, 4.68±1.07 mm, and 2.68±0.71 mm, respectively. No significant difference was observed between the measurements in terms of sex and sides. Apart from SRA, the parameters were greater in the third-trimester fetuses than the second-trimester fetuses. SRA was similar in both trimester fetuses. SRA did not alter with advancing gestational weeks, but the other increased. In fetuses, only one configuration regarding SRA types was observed. Type A was observed in all fetuses. Linear function was calculated as y=1.411 + 0.902×age for SRL, y=-0.137 + 0.281×age for SRW-ML, and y=1.024 + 0.069×age for SRW-L.

Conclusion: Our study provides beneficial data for neurosurgeons and anatomists to understand the development of SR in the prenatal period. The authors' regression equations for determining the growth dynamics of the ridge may be used to estimate SR parameters.