Radiologic Evaluation of Developmental Anomalies of The Odontoid Process: A Cone-Beam-Compated Tomography Study

Background: The odontoid process is an anchoring pivot for the craniovertebral junction and has many congenital anomalies. Ossiculum Terminale Persistans (OTP) and Os Odontoideum (OO) are believed to be rare developmental anomalies of the odontoid process. The OTP is defined as an ossification center that gives rise to the tip of the dens failing to fuse properly with the body of the axis. OO is described as an oval-shaped, well-corticated bony ossicle that is positioned cephalad to the body of the axis. Both of these conditions may cause neurological signs and atlantoaxial instability.