Normal MR imaging anatomy of the ankle and foot in the pediatric population.

MR imaging demonstrates the cartilaginous primordia of the bones of the foot and ankle. Ossification of the round bones begins in a single center and extends along the length of the bone. There is a difference between the orientation of the ossification center and that of the main cartilaginous structure. MR imaging can show the zones of the cartilage and the changes that precede ossification. The changes in the cartilage and marrow at different ages are illustrated for the ankle, hindfoot, and midfoot.