Wormian bones are small bones mainly occurring in the lambdoid sutures
of the skull.
These can be normal variants and usually do not mimic fractures. Excessive wormian bones are associated with certain congenital syndromes such as osteogenesis imperfect, menke syndrome, cleidocranial dysostosis, and pyknodysostosis to name a few which are quite rare. Usually involve defective mineralization.