Objective: The aim of the present study was for the first time to examine on postmortal material the total midpalatal length of the hard palate and the length of its two components (the maxillary and palatine parts) in trisomy 21 fetuses, and to compare the results to normal standards.
Design: Material from 31 human fetuses with genetically verified trisomy 21 was studied. The fetuses were derived from legally induced or spontaneous abortions. Palates were, after sectioning, radiographed in lateral projection (Grenz Ray radiographic apparatus). Cephalometric measurements were performed with a digital caliper. Statistically, the length measurements for the two groups were compared, adjusting for crown rump length (CRL) through linear regression. At two specific ages (150 and 170 mm CRL), the length of the palatal components in trisomy 21 was compared to normal standards.
Results: For CRL 150 mm and CRL 170 mm it appears that all three palatal lengths, total length, maxillary length, and palatinal length are significantly shorter in fetuses with trisomy 21.
Conclusion: The main conclusion of our study is that the total palatal length in prenatal trisomy 21 is shorter than normal and that this is due both to a shortness of the maxillary and the palatine components of the hard palate.