hyperostosis

n excessive enlargement of the outer layer of a bone. The condition is harmless and is usually recognized as an incidental finding on X-ray. It commonly affects the frontal bone of the skull (hyperostosis frontalis). Infantile cortical hyperostosis (or Caffey's disease) affects infants under six months. There is swelling of the long bones, jaw, and shoulder blade, with pain and a fever. The condition settles spontaneously.