Rickets: (a) Before treatment, uniform physeal widening and metaphyseal irregularity and flaring affect the knee of this 2-year-old black child with vitamin D deficiency, poor dietary Ca²⁺ intake, and seizures treated with phenobarbital. (b) Physes are widened and metaphyses are irregular and flared in the right wrist of this 2-year-old girl with untreated X-linked hypophosphataemia. A ‘ball-in-cup’ deformity is developing at the distal radius. (c) Physeal widening is less apparent in the left knee of this 2-year-old girl beginning treatment for X-linked hypophosphataemia. Asymmetrical physeal widening is due to the bowing deformity of the lower limbs. Also, there is beaking of the medial tibial metaphysis.