Inferior Accessory Ossicle of Anterior Arch of Atlas: Case Report with 3D Visualisation

Abstract

Inferior accessory ossicle of anterior arch of atlas is a rare, albeit normal variant in relation to the cervical spine, invariably detected incidentally while investigating for other unrelated condition. Its existence should always be kept in mind while evaluating any bony fragment in relation to atlas axis vertebrae so as to avoid unnecessary investigation in suspicion of other sinister aetiology. The presence of well-cortical margins, constant size and shape over a course of time, constant position in close relation to anterior atlas arch, normal appearing pre-paravertebral soft tissue are indicators of its presence. We present a case of this anatomical variant detected incidentally in an old man investigated for oral malignancy.

Keywords

• atlas
• accessory
• ossicle
• sesamoid