Craniovertebral junction anomalies

Last revised by Dr Patrick J Rock on 13 May 2021

Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to any acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression, and obstructive hydrocephalus.


The craniovertebral junction is formed by the occipital condyles, atlas (C1), axis (C2) vertebrae, and their articulations. Any process which can give rise to malformation of these structures may result in a CVJ anomaly. It can be due to a congenital, developmental, or acquired cause. 

On this basis of etiology, CVJ malformations can be classified as:

Congenital anomalies and malformations
Malformations of the occipital sclerotome
Malformations of atlas vertebra
Malformation of axis and odontoid process
  • atlantoaxial fusion
  • persistent ossiculum terminale
  • os odontoideum
  • odontoid dysplasia
Developmental and acquired malformations
Malformations at the foramen magnum

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1: achondroplasia
    Drag here to reorder.
  • Case 2: atlanto-occipital assimilation
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.