Thinning of the clavicular cortex in adults under the age of 45 in osteomalacia and hyperparathyroidism.

A study involving 18 patients shows that thinning of the upper cortex of the clavicle in adults under the age of 45 is most commonly due to renal osteodystrophy or coeliac disease. Cortical thinning should not therefore be regarded as synonymous with osteoporosis. Cortical thinning is usually associated with clavicular erosion in renal osteodystrophy but not in osteoporosis or osteomalacia. The radiological diagnosis of coeliac disease is suggested when thinning of the clavicular cortex is combined with air--fluid levels on abdominal radiography in a patient under the age of 45 years.