Prenatal growth of human ulna and estimation of CRL and CHL based on osteometry on fetal ulna

In dealing with fetal bone growth and fetal age estimation from osteometry, the earlier osteometric studies were done from chemically preserved fetuses, photographs, radiographs and ultrasonographs which would not give perfect results. In the present study osteometry was taken directly on naturally prepared fetal ulna bones for the first time. There were six new osteometric measurements on human fetal ulna introduced.Possible osteometric measurements were taken on 912 fetal ulna bones (right and left) from 456 fetuses having age range between 11 weeks to 40 weeks of intrauterine life. Bilateral and bisexual differences were analyzed. It is found that there is positive growth trend found in fetal ulna on the basis all the osteometric measurements taken on fetal ulna. The fastest rate of growth in the length of fetal ulna was observed in females during 11 weeks to 16 weeks of the intrauterine life of human fetus. For every 1 mm in the CRL (crown- rump length), the Maximum Length of Ulna is increased by .306 mm. As there is no established scale available for fetal age estimation from fetal bones, even anatomists found difficulties to provide precise opinion regarding the age of human fetus from fetal bones in suspected murder cases. In the present study regression values were calculated and found out a formula to estimate CRL and CHL (crown-heel length) from the osteometric measurements on fetal ulna. The age estimation is a crucial factor in dealing with medico-legal cases