Introduction
Craniovertebral junction (CVJ) is a junction with a complex structure consisting of ligaments providing stability for the bones and joints between the head and spinal column. Bony structures in this junction are occipital bone (1) including the foramen magnum, clivus, and condylar process and the first two vertebrae of the cervical spinal column: atlas (C1) and axis (C2). Atlanto-occipital joint (AOJ), atlanto-dental joint (ADJ), and atlanto-axial joint (AAJ) are present in this complex structure. There are multiple ligaments and membranes providing stability on the joint structures, however, the most important of those are cruciate and alar ligaments. C1 and C2 vertebrae together with the other joints in this region help to move the head. While AOJ is responsible for the anterior and posterior movement of the head, ADJ is responsible primarily for the axial rotation of the head. Cranio-cervical junction (CCJ) is the region where the brainstem, spinal cord, some cranial nerves, and vertebral arteries are located and preserved. Numerous congenital or acquired (traumatic, inflammatory) pathologies can affect the CVJ. Among the congenital pathologies, atlanto-occipital assimilation (AOA), Klippel-Feil syndrome (KFS), and similar rare segmentation and ossification abnormalities, malformations like Os Odentoideum (OO) can narrow the spinal canal and can lead to myelomalacia and neurological findings by compressing the spinal cord (1-3).
In this study, we aimed to present the patients who was performed cervical tomography due to various complaints and had congenital pathologies originated from odontoid proses in the CVJ region causing dislocation, myelomalacia, and neurological complications.