Human fetal hand size and hand maturity in the first half of the prenatal period.

The purpose of the present study has been to establish radiographic standards of hand length and finger bone size in the first half of the prenatal period, and to relate these measurements to general fetal size (CRL) and foot length (FL), as well as to the skeletal maturity assessed from a Composite Number of Ossified bones in hand and foot radiographs (CNO). The right hand and foot of each of 251 normal human fetuses (CRL 47-194 mm) were radiographed. From each hand radiograph hand length (DM), third proximal phalangeal bone length (PP) and third metacarpal bone length (MC) were measured. The study showed that third proximal phalangeal and metacarpal bone lengths both provide a valuable basis for estimating hand length. Both hand length and the length of the third metacarpal bone were found to be good predictors of general fetal size (CRL). The study provides standards for the relationships between hand and finger bone sizes, general fetal length and foot length. By combining third metacarpal bone size and skeletal maturity of the hand and foot general fetal development (age and crown-rump length) can be estimated. Insight into normal hand size and finger bone size at different stages of normal development including skeletal maturation is useful in future evaluation of handsize under pathological conditions.