Cranio-Vertebral Junction ( CV Junction)

Cranio-Vertebral Junction is the bony junction of the skull and vertebral column. It is formed by Clivus, Occipital bone and C1 and C2 vertebra.

This area is important as any abnormality in this area may lead to compression over the cervico- medullary junction, which is the junction of the cervical region of the spinal cord qnd medulla oblongata.

The abnormality at this region could be congeital anomaly or acquired.

This is simple diagram of the sagittal view shows location of CV Junction. TOO is abbreviation for transoral odontoidectomy . This surgery is done through oral cavity . Anterior arch of Atlas vertebra ( first cervical vertebra)  lies just anterior to the odontoid process of Axis vertebra ( 2nd cervical vertebra). Any dislocation of Atlanto-Axial Joint ( Atlanto axial dislocation -AAD) may compress over the medulla Oblongata, which lies just posterior to the Dens of the C2 vertebra.

Stability of the CV junction is mainly due to ligaments. 

The anterior atlanto-occipital membrane is the cranial extension of the anterior longitudinal ligament. It extends from anterior margin of foramen magnum to anterior arch of C1.

Posterior Atlanto-occipital membrane connects posterior margin of the foramen magnum to the posterior arch of Atlas.

Tectorial Membrane is the upward continuation of posterior longitudinal ligament. It connects the dorsal surface of the Dens of the Odontoid process of C2 vertebra anterior lip of the Foramen magnum.

Apical odontoid Ligament connects the tip of Dens to the anterior lip of Foramen Magnum.

Alar Ligament  connects side of the Dens to occipital condyles.

Transverse Ligament is the horizontal component of the Cruciate ligament which traps or straps or binds the Dens anteriorly against the C1. It is the strongest ligament.