Occipitalisation of Atlas with Sudden Onset

Occipitalisation of Atlas with Sudden Onset

Occipitalization or assimilation of the atlas, atlanto-occipital fusion and occipito-cervical synostosis are synonyms and indicate a fusion of C1 to the base of the skull. This condition was initially described by Rokitansky in 1844 and was demonstrated radiologically by Schuller in 1911. Atlo-occipital fusion can be complete or partial, unilateral or bilateral and bony or fibrous. Its incidence is reported from 0.14 to 3.63% according to different authors in the whole population, with equal repartition in both sexes and it is considered the most common anomaly of the cranio-cervical junction.