Cranial dysraphism mistaken for trephination.

Attention is called to a disputed diagnosis of trephination reported for a perforated skull of a prehistoric New England Indian. The perforation, surrounded by a saucer-like depression, is located exactly in the midline just in front of bregma. The finding of a similar lesion in a prehistoric Indian skull from the North Coast of Peru--where, as in New England, good evidence of the practice of trephination is lacking--provides support for a more reasonable diagnosis for both cases: congenital cranial dysraphism, specifically encephalocele. Information about dysraphic states from modern clinical experience is summarized.