The degree of bone mineralization in different parts of human skeleton estimated from bone phosphorus/hydroxyproline

To evaluation the uniformity of the degree of mineralization in the skeleton the bone phosphorus/hydroxyproline ratio (bone P/Hypro) was determined in different localizations of ten human skeletons. Marked differences in bone P/Hypro were found between cortical bone and spongy bone. No difference was found between cortical bone from humerus, femur and cranium. But the mean value of these cortical bones was significantly higher than the mean value of the studied spongy bones. No significant correlation was found between the two bone types. Differences in bone P/Hypro were also found between different spongy bones. In pelvis the value did not differ between four spongy bone localizations but the mean value was significantly lower than for the other spongy bones (thoracal column, lumbal column and clavicle). Between these other spongy bones no difference was found in mean bone P/Hypro, and the mean of the pelvic bone localizations correlated significantly to the other spongy bones. The study demonstrates differences in the chemical composition of the human skeleton. A value of bone P/Hypro in the iliac crest can be used to estimation of bone P/Hypro in other spongy bones but not in cortical bones.