Aplasia parcial congénita de arco posterior de atlas.

Partial aplasia of posterior arch of the atlas are rare but well documented anomalies, most cases are asymp- tomatic but cases of myelopaty and quadraparesis associa- ted to defects of posterior arch of the atlas have been publis- hed in the past. Case 1: female, 31 years old, suffered traffic accident with neck and upper limb pain. Partial aplasia of posterior arch to the atlas was detected in X-Rays, at the moment the patient continues with neck pain. Case 2: female 28 years old who referred neck pain after traffic accident, partial aplasia of posterior arch of the atlas was detected. Bibliographic review.