Evaluation of fetal midface anatomy related to facial clefts: use of US.

Purpose: To identify the sonographic appearance of normal fetal midface anatomy of in vitro fetal specimens and to correlate the appearance with that of in utero fetuses to determine which aspects of this anatomy can be evaluated clinically.

Materials And Methods: The midface structures of 12 normal fetal specimens were examined in the axial, sagittal, and coronal planes with ultrasound. The results were correlated with those of other modalities. One hundred consecutive, normal in utero fetuses were scanned in the same planes in an attempt to identify the same anatomic landmarks identified in the fetal specimens.

Results: In the fetal specimens, the upper lip (coronal plane), alveolar ridge, tooth sockets, point of fusion of primary and secondary palates (axial plane), and fusion line of the secondary palate (sagittal plane) were consistently observed. In the 100 in utero fetuses, the same anatomy was visualized in the coronal plane in 95 (95%), in the axial plane in 97 (97%), and in the sagittal plane in 26 (26%). The mean scanning time was 2.8 minutes.

Conclusion: Important aspects of fetal midface anatomy that relate to facial clefts can be observed in utero at prenatal sonography in the coronal and axial planes.