[Cephalometric study of the cranial base in 133 cases of Down's syndrome].

: Previous studies in patients with Down's syndrome have revealed signs of major anomalies of base of skull. A cephalometric radiography study was conducted to determine extent of these anomalies by quantitative methods. Skull morphology and structure were investigated in two groups of patients with Down's syndrome in whom cytogenetic analysis had demonstrated the presence of an extra chromosome in group G. The first group included 100 patients of both sexes aged between 9 and 30 years, the second group consisted of 33 patients aged 5 to 19 years. A matched control group was also studied. Cephalometric analysis (Bjork, Delaire) showed shortening of anterior segment of base of skull in patients with Down's syndrome, as well as an increase in angle of base of skull when compared with controls, the differences being statistically significant.