Changes in the composition of the human femur during growth

Abstract

Rickets used to be a common disease of young children, and a number of the early investigators of bone chemistry (Friedleben, 1860;Schabad, 1910) were primarily interested in the changes induced by this disease.Studies of the effect of development have more recently been reported, but, for the most part, these have been limited to a particular part of the life-span or to a particular part of a bone.The study of Swanson & Iob (1937) was confined to the mineral composition of the bone and cartilage of the human foetus.Baker, Butterworth & Langley (1946) reported on the calcium and nitrogen in human bone tissue; they found that the calcium/nitrogen ratio of the cancellous bone of the rib was higher in adults than it was in infants.This aspect of the problem was again taken up by Rogers, Weidmann & Parkinson (1952), who analysed 40 samples of femoral cortical bone from persons varying in age from 8 months to 90 years.They found that there was a rise in the calcium/ nitrogen ratio between the ages of 8 months and 20-30 years and, examining samples from a few of the subjects, found that collagen accounted for 89-96 % of the total nitrogen at all ages.Similar information about the changes in composition of human bone during foetal and early postnatal life does not appear to be available (Wallgren, 1957).The purpose of the present paper is to report the results of a study of femora from 62 human subjects ranging in age from 12 weeks' gestation to 35 years.At all ages cortical bone from the middle third of the shaft and, up to 12 years of age, the epiphyses, have been separated and analysed.The remainder of each bone has also been analysed and the composi- tion of the whole bone obtained.The study is similar to that reported on the long bones of the pig, rat and fowl (Dickerson, 1962). METHODSFemora were obtained from 21 foetuses of 12-28 weeks' gestation, which were delivered for a variety of reasons, but all were anatomically normal.The approximate age of these foetuses was calculated from the crown-heel length according to the formula derived by Scammon & Calkins (1929).Femora were also obtained from six foetuses of 30-34 weeks' gestation, eight full-term stillborn babies, 22 babies aged 2 days to 24 months, two children of 11 and 12 years respectively, two youths of 16 years, four women