Normal Values:

The normally developing fetus should have values that fall within these ranges (5th - 95th percentiles):

Thoracic Circumference (cm): ~

Femur Length (mm): ~

References

Prenatal sonographic assessment of the fetal thorax: normal values.
Chitkara U, Rosenberg J, Chervenak FA, Berkowitz GS, Levine R, Fagerstrom RM, Walker B, Berkowitz RL.
Am J Obstet Gynecol. 1987 May;156(5):1069-74.
New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study.
Verburg BO, Steegers EA, De Ridder M, Snijders RJ, Smith E, Hofman A, Moll HA, Jaddoe VW, Witteman JC.
Ultrasound Obstet Gynecol. 2008 Apr;31(4):388-96.