A case of combined congenital anterior and posterior arch anomaly of C1 vertebra

A very rare case of the craniovertebral junction (CVJ) anomaly is reported owing to its rarity and clinical significance. Computed tomography (CT) and magnetic resonance imaging (MRI) studies of the cervical spine of a 56 -year-old female patient presented with head trauma, revealed an anterior midline arch cleft of atlas with totally aplastic posterior neural arch, as well as anteriorly subluxed right atlantoaxial joint. The coexistence of a total aplasia of the posterior neural arch and anterior arch cleft of atlas is very rare. Congenital anomalies affecting the craniovertebral junction (CVJ) may mimic traumatic injury in the setting of a previous trauma. In this presented case, the absence of an associated bone and soft-tissue edema on the MR imagings helped us to make a differention between the acute traumatic injury and congenital anomaly