Assimilation of the atlas with associated syringomyelia and Chiari 1 malformation (Klippel-Feil type 2).

This case report describes an unusual congenital anomaly of the craniovertebral junction in a 14 year old male. Cervical radiographs showed the bony anomaly, while thin slice CT (with 2-D and 3-D reformations), MR imaging, and angiography were particularly useful in accurately assessing the bony, soft tissue and vascular anatomy, prior to and following surgery.