Cervical myelopathy from atlantal hypoplasia and torticollis.

Cervical myelopathy caused by atlantal hypoplasia has been reported in only 11 patients. Atlantal hypoplasia combined with torticollis has not been reported. Rotation of the atlantoaxial joint causes spinal canal narrowing at the atlantoaxial level and stretches the vertebral artery, which may aggravate the symptoms and signs of compressive cervical myelopathy from atlantal hypoplasia. We present a patient with cervical myelopathy from atlantal hypoplasia, retrodental pseudotumor, and torticollis.