Morphometric Evaluation of Craniofacial and Alveolar Arch Structures in Anencephalic Human Fetuses: A Cadaveric Study

Objective: The aim of the present study was to compare the morphometrics of the craniofacial and alveolar arch structures of anencephalic fetuses with those of normal human fetuses without anencephaly or any other anomaly. Design: Original article. Methods: Standard lateral and posteroanterior cephalometric radiographs of 23 anencephalic and 33 normal human fetuses aged between 21 and 40 weeks of gestation were compared. These fetuses were divided into three periods based on gestational age, and vertical, sagittal, transverse, and angular measurements were taken in the cranial base and facial regions. Moreover, intraoral measurements from the maxillary and mandibular arches were also made to determine the width and depth. Results: N-S and S-Ba lengths and the N-S-Ba angle, measured on lateral cephalometric radiographs, were statistically smaller in anencephalic fetuses (p < .05). The S-N-ANS, S-N-Pg, and ANS-N-Pg angles and the Go-Me length were significantly greater in anencephalic fetuses (p < .05). Maxillary length, ramus length, and anterior facial heights were similar in both groups. On posteroanterior radiographs, all parameters except bigonial distance were found to be smaller in the anencephalic fetuses (p < .05). Maxillary alveolar width was small among anencephalic fetuses in all three periods; whereas, the mandibular alveolar width was narrow only in the third period. Conclusion: Cranial and facial structures were affected morphometrically to various degrees in anencephalic cases. The most significant alterations in anencephalic cases were related to measurements in the transverse direction. This indicated that cephalic tissue influenced not only the cranial base but also all facial structures.