History: pediatric patient with bowed legs. 

This is a classic case of Rickets, which is a metabolic bone disease caused by lack of calcium and phosphate, which is commonly due to vitamin D deficiency. This leads to softening of the bones due to failure to mineralize bone. Causes of rickets in children less than 6 months old include prematurity and hypophosphatasia. In children greater than 6 months old, dietary and sunlight deficiencies are common causes, as well as renal failure, liver disease, malabsorption, and renal tubular disorders.

Radiographic manifestations of rickets include widened metaphyses, and metaphyseal cupping, splaying, and fraying as seen in the second image above. The differential diagnosis for these radiographic findings includes leukemia, child abuse with metaphyseal fractures, congenital syphillis (Wimberger’s Sign), gymnast wrist, and physeal fractures.

The “rachitic rosary” seen in the first image above is secondary to costochondral junction widening. This creates a row of beads under the skin on clinical exam, hence the term rachitic rosary (seen in the image below).

Photo resource: http://en.wikipedia.org/wiki/File:Rosary_2006-01-16.jpg

Thank you to Quinn Meisinger, M.D. for these excellent images of rickets.

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