Right juxtacondylar bony facet on the basiocciput: a proatlas segmentation variant

The cranio-vertebral region is a region of spine with a high level of variability. Presence of unusual bony masses at or near the foramen magnum may lead to craniocervical instability and also cause compression at the spino-medullary junction leading to vascular and neurological signs and symptoms. This article documents the presence of a basilar bony facet located medial to the right occipital condyle along the rim of foramen magnum, extending just beyond the middle of the anterior margin. The embryological and clinical bearings of such variant at the cranio- cervical junction are discussed.