Abnormal structure of the odontoid process, which is a part of the C2 or axis vertebra and forms pivot of the structures forming the craniovertebral junction. The odontoid process is also known as the dens of the axis.
Abnormal sacrum morphology +
Abnormal thoracic spine morphology +
Abnormal vertebral morphology +
Abnormality of the cervical spine +
Aplasia/Hypoplasia involving the vertebral column +