Occipitalization of the atlas: its occurrence and embryological basis

Abstract

Occipitalization of the atlas is a rare congenital malformation of the craniovertebral region. During anthropometric study of 126 human skulls in the Department of Forensic Medicine and Anatomy, two skulls were discovered, which exhibited assimilation of the atlas to the occipital bone. One female skull exhibited total assimilation with bifid posterior arch, while the other male skull exhibited partial occipitalization and partial vertebralization. The partial or complete assimilation of the atlas may have resulted due to disruption in the separation of the caudal part of the first sclerotome from the cranial part of the first sclerotome.