Sudden unexpected death associated with atlanto-occipital fusion.

A case of sudden, unexplained death in a 24-year-old male is presented. There were two previous spells of loss of consciousness. There was remarkable narrowing of the foramen magnum with indentation of the medulla. The atlas was partly fused with the occipital bone and a portion of abnormal bone compromised the foramen magnum from anterior reducing its anteroposterior dimensions to 16 mm (n 25-35 mm). Close clinical examination of this area in patients with acute intermittent symptomatology, or at the time of autopsy in cases of sudden unexpected death is stressed.