E2460. Pictorial Essay of Craniovertebral Junction Anomalies
Lohia Institute of Medical Sciences
To outline a few characteristic congenital anomalies of the CVJ in the form of a pictorial presentation.
The Craniovertebral junction (CVJ) is a collective term that refers to the occiput, atlas, axis and supporting ligaments which encloses soft tissue structures of the cervical medullary junction.(1)
A variety of congenital anomalies with the potential for causing neurological deficits occur in this region.(2)
Computed Tomography and Magnetic Resonance Imaging are rewarding in the detailed evaluation and diagnosis of common and uncommon abnormalities of the CVJ.(1)
Educational Goals / Teaching Points
Multiplanar reconstruction in coronal & sagittal planes were done after obtaining axial CT images.
Craniometric measurements used in radiologic assessment of CVJ anomalies include the Chamberlain line, Wackenheim clivus baseline, Welcher basal angle, and atlantooccipital joint axis angle.
A pictorial representation of few of the representative congenital anomalies of CVJ are included in this study.
Congenital Anomalies of Occiput
Condylar hypoplasia and Atlanto occipital assimilation
Congenital anomalies of atlas
Posterior arch hemiaplasia and aplasia
Fusion anomaly of Atlas
Congenital anomalies of axis
Persistent ossiculum terminale
Klippel Fliel Syndrome
Atlanto axial instability
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Occipital condylar hypoplasia
Short, flat occipital condyles
Widening of atlanto occipital joint axis angle
Normal range : 124 to 127 °
Skull base is flattened and ascends medially
Atlanto occipital assimilation
Failure of segmentation between skull and first cervical vertebra
Complete or partial
Invariably results in basilar invagination
In some cases may be associated with sudden death
Posterior arch hemiaplasia
Axial CT image shows absence of the right posterior arch of atlas
Aplasia of posterior arch of C1 with persistent posterior tubercle
Axial CT image shows absence of posterior arch of atlas and persistent posterior tubercle.
Craniovertebral junction is a unique transition between the mobile vertebral column and fixed cranium.
A thorough understanding of the anatomy and anomalies is necessary for appropriate treatment planning.
This presentation has focused on outlining few of the congenital anomalies of the CVJ using representative MR or CT images.