[Sonographic study of Béclard's nucleus as a method of determining the maturity of the newborn infant].

The size of the distal femoral epiphysis is an important criterion for determining the maturity of a neonate. The distal femoral epiphysis has been demonstrated and measured sonographically in two planes during the first month of life in 174 neonates. The sum of the epiphyseal diameters has been related to gestational age. The average sum of the sagittal and transverse diameter of both distal femoral epiphysis was 10.9 mm in the 35th week (standard deviation 7.6 mm) and increases to 38.4 mm at 43 weeks (standard deviation 6.3 mm). Linear regression of the mean values of the sum of the epiphyseal diameters y against gestational age x shows a correlation coefficient of 0.95 (regression gradient y = -117.7 + 3.7 x). Sonographic demonstration and measurements of the distal femoral epiphyses is a valid alternative to radiological examination.