Fig. 1-93: Eęample of takmg measurements of 3 rib cross sec-doiis with their corrssponding mtercostal spaces in a fetus on Day 138 of pregnancy. The iength of one rib cross section with its corresponding mtercostal space is 1Z5 mm (373 divided by 3).
Fig. 1.94: Example of measuring the diameter of the tiunk a fetus on Day 88 of gestation.