What the mind does not know, the eyes do not see: a rare congenital fusion of the odontoid process to the atlantal hemiarch

Duplication of the odontoid process with other congenital defects of the craniocervical Junction: case report and review of the literature

Duplication of the odontoid process remains a rare developmental pathology that is underrepresented in the current literature. As the pivot point for the craniovertebral junction, the odontoid process is vital for the integrity of the atlanto-axial joint and the ability of the head and cervical spine to rotate correctly. The pathogenesis being incompletely understood, it has been proposed that odontoid process duplication involves faulty sclerotome migration and disruption of the axis ossification center. Patients presenting with this pathology usually have associated structural abnormalities. A detailed anatomical and embryological understanding of the odontoid process is necessary for successful management and treatment of patients presenting with odontoid process duplication. We present a rare case of a patient with a duplicated odontoid process in association with C2–C3 fusion, incomplete anterior arch of C1, variant inferior bony process of the transverse process of C1, and enlarged right jugular foramen.