Congenital fusion of C2 - C3, Radiology Case

Fusion of adjacent vertebral segments is not an unusual isolated abnormality and should not be confused with the far less common Klippel Feil syndrome. 

Klippel Feil Syndrome

C1–T2 decompression and fusion for C2 erosive pannus—a case report

My unknown birth defect : r/Radiology

Reduction of cervicothoracic spondyloptosis in an ambulatory patient: when traction fails

Congenital fusion of C2 - C3, Radiology Case

Cervical instability in Klippel-Feil syndrome: case report and review of the literature, Chinese Neurosurgical Journal

Atlanto-occipital assimilation, Radiology Reference Article

Children, Free Full-Text

Part 9: Spine Radiology Key

Radiology In Ped Emerg Med, Vol 5, Case 5

Congenital Cervical Spinal Deformities - ScienceDirect

Diagnostics, Free Full-Text

Klippel Feil Syndrome

Block vertebra - C2/3, Radiology Case