Abstract: The measurements on 85 Chinese atlases (46 male and 39 female) have been taken. The main results are as follows.
1. The total transverse diameter (X1) and the antero-posterior diameter (X2 ) of the atlas are 45. 98±0. 46 mm and 78. 36±0. 57 mm in male, 42. 06±0. 37 mm and 70. 9土0. 54 mm in female, respectively.
2. The maximum transverse diameter of the vertebral foramen and the anteroposterior diameter of the vertebral foramen are 29. 76±0. 27 mm and 27. 75±0. 29 mm in male, 27. 75±0. 26 mm and 25. 90±0. 29 mm in female, respectively.
3. The sexual discriminant function is Z=X1+2. 21098 X2, (X1=breadth, X2 = sagittal diameter) and its critical value is Zo=172. 9102. 12. 9-18. 5% of all cases are the miselassified.

Key words: Atlas; Discriminant function; Coefficient