Abstract
By expressing the mineral content of the ulna at 1 cm to that at 8 cm from its distal end as a ratio, a measure of the amount of trabecular bone in that ulna is obtained. This ratio is occasionally high in patients with primary hyperparathyroidism and commonly high in patients with hyperparathyroidism secondary to azotemic renal failure. A hypothesis based on calcitonin and a speculation about its mode of action are used to account for some of the findings in primary and secondary hyperparathyroidism .