Sella turcica and facial bones: Morphological integration in the human fetal cranium

Abstract

OBJECTIVES: The cranial base plays a significant role in facial growth, and closer analyses of the morphological relationship between these two regions are needed to understand the morphogenesis of the face. Here, we aimed to study morphological integration between the sella turcica (ST) and facial bones during the fetal period using geometric morphometrics. MATERIALS AND METHODS: Magnetic resonance images of 47 human fetuses in the Kyoto Collection, with crown-rump lengths of 29.8ー225 mm, were included in this study. Anatomical homologous landmarks and semilandmarks were registered on the facial bones and the midsagittal contour of the ST, respectively. The shape variations in the craniofacial skeleton and the ST were statistically investigated by reducing dimensionality using principal component analysis (PCA). Subsequently, the morphological integration between the facial bones and ST was investigated using two-block partial least squares (2B-PLS) analysis. RESULTS: PCA showed that small specimens represented the concave facial profile, including the mandibular protrusion and maxillary retrusion. The 2B-PLS showed a strong integration (RV coefficient = 0.523, r = .79, p < .01) between the facial bones and ST. The curvature of the anterior wall of the ST was highly associated with immature facial morphology characterized by a concave profile. CONCLUSION: The strong integration between the two regions suggested that the anterior ST may be associated with facial morphology. This result quantitatively confirms previous studies reporting ST deformities in facial anomalies and induces further research using postnatal subjects.