Auxiliary Wings of the Axis.

Abstract

Bony anomaly of axis (C2) vertebra is well known. However, expansion of the posterior element is less documented. We describe a case of additional bony ring attached to the posterior spinous process in a 10-year-old male who presented with the complaint of progressive swelling at the upper cervical region. On physical examination a firm swelling approximately 8 × 5 cm was present at the back of the neck just below the hair line. There was no focal neurologic deficit. Computed tomography scan of the cervical spine showed an additional bony arch attached to the spinous process of the C2 vertebra. Magnetic resonance imaging revealed a soft tissue mass within the additional bony ring without involvement of neural structures. Complete surgical excision of the mass was done. Anomalous expansion of the spinous process of the C2 vertebra may remain silent. Surgery may be necessary for cosmetic purposes.