Abstract: Objective　To analyze cerebellum development with gestational age and to evaluate clinical early cerebellum development,  by means of cranial ultrasound to measure the neonatal cerebellum for gestational age of 25 to 41 weeks on the day of birth.　Methods 　Three hundred and eighteen eligible cranial ultrasound images of neonates of appropriate for gestational age from 25 to 41 weeks were selected. Transverse cerebellar diameter, vermis height, vermis diameter, vermis circumference and vermis area were measured for statistical analysis.　Results　Transverse cerebellar diameter formed a linear equation with the gestational age, which was Y=0.1036X+0.1929 (R2=0.727，P<0.001). Vermis height formed a linear equation with the gestational age, which was Y=0.069X-0.3156 (R2=0.823，P<0.001). Vermis diameter formed a linear equation with the gestational age, which was Y=0.0509X-0.5798 (R2=0.735，P<0.001). Vermis circumference formed a linear equation with the gestational age, which was Y=0.2811X-1.5932 (R2=0.782，P<0.001). Vermis area formed a linear equation with the gestational age, which was Y=0.2283X-4.4559 (R2=0.817，P<0.001). The vermis height had the strongest positive correlation with the gestational age (r=0.907，P<0.001). Conclusions   The results of this study provide that the cerebellar extrauterine reference range among transverse cerebellar diameter, vermis height, vermis diameter, vermis circumference, vermis area of neonates of appropriate for gestational age and gestational age, which is helpful for clinical diagnosis and evaluation of cerebellum growth and development of newborns.

Key words:  , Cerebellum, 　Cranial ultrasound, 　Neonatal infants, 　Gestational age