During the last ten years, the diagnostic approach to disorders of bone and mineral metabolism has benefited considerably from the development of radioimmunoassay and competitive protein binding techniques for measurements of circulating parathyroid hormone, calcitonin, and biologically active vitamin D me tabolites. Accumulated experiences with radiogrametrical and densinometric methods of quantitating appendicular bone mass now facilitate the detection of changes in bone mineral content heretofore unrecognized by routine roentgenographic vertebral analysis. During this same decade, the...