Wormian bones

Wormian bones = extra ossicles within cranial sutures, especially lambdoid.

They can be normal variants, but multiple (>10) or very large ones → think underlying disease.

1. Collagen / bone dysplasia group
   • Osteogenesis imperfecta (#1 association)
   • Cleidocranial dysplasia
   • Pyknodysostosis
   • Hypophosphatasia
2. Metabolic
   • Rickets
   • Hypothyroidism (cretinism)
3. Syndromic
   • Down syndrome
   • Menkes disease (kinky hair)