Imaging the craniocervical junction

Area of Science:

• Radiology
• Orthopedic Surgery
• Developmental Biology

Background:

• The craniovertebral junction (CVJ) involves the occiput, atlas, and axis.
• Radiographic assessment requires knowledge of specific anatomical landmarks and measurements for craniometry.
• Anomalies of the occiput, atlas, and axis can lead to conditions like basilar invagination.

Purpose of the Study:

• To provide a comprehensive review of CVJ anatomy and craniometry.
• To illustrate congenital anomalies of the occiput, atlas, and axis.
• To discuss common syndromes associated with CVJ pathology.

Main Methods:

• Review of anatomical landmarks and normal measurements for CVJ craniometry.
• Illustration of various congenital anomalies of the occiput, atlas, and axis.
• Discussion and illustration of common syndromes affecting the CVJ.

Main Results:

• Occipital bone anomalies and atlanto-occipital non-segmentation often cause basilar invagination.
• Atlas anomalies typically affect the posterior arch.
• Os odontoideum is the most frequent anomaly of the axis.

Conclusions:

• Syndromes such as Klippel-Feil, Down syndrome, achondroplasia, mucopolysaccharidoses, and osteogenesis imperfecta are linked to CVJ pathology.
• Skull-base softening in certain syndromes can result in acquired basilar invagination or impression.
• Understanding CVJ anatomy and craniometry is crucial for diagnosing these congenital and acquired conditions.