Embryonic brain measurements. (A) Midsagittal plane showing the place (yellow line) where the axial plane is made to perform the embryonic brain measurements, 9 weeks of GA. (B) Axial plane, 9 weeks of GA; 1 = DTD, 2 = MTD, 3 =TTL, 4 = TTR. (C) Axial plane, 11 weeks of GA; 1 = DTD, 2 = MTD, 3 = TTL, 4 = TTR. (D) Diagram of the axial plane, 11 weeks of GA, 1 = DTD, 2 = MTD, 3 = TTL, 4 = TTR. GA, gestational age; DTD, diencephalon total diameter; MTD, mesencephalon total diameter; TTL, telencephalon thickness left; TTR, telencephalon thickness right.