Cureus. 2019 Apr 6;11(4):e4402. doi: 10.7759/cureus.4402.

Gnanadev R, Ishak B, Iwanaga J, Loukas M, Tubbs RS.

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Abstract

Atlantooccipital assimilation is defined as the complete or partial fusion of the caudal portion of the occiput with the cranial portion of the atlas. We report an extremely rare case of a traumatic dislocation of the atlas from the axis (C1 from C2), which lead to internal decapitation in a patient with atlantooccipital assimilation. This report reviews the background of atlantooccipital assimilations and their clinical relevance.

KEYWORDS:

assimilation; congenital; craniocervical; trauma

Figure 1

Lateral radiograph of the craniocervical junction and upper cervical spine noting that the white arrows point to the assimilated atlas (left) and bare odontoid process of C2 (right)