Anomalies around the foramen magnum are of clinical importance, closely related to nervous and vascular structures. In one of the skull, a tubercle was found at the anterior margin of foramen magnum projecting into foramen magnum, formed of exostoses in the apical ligament of dens. Could be one of the “manifestation of occipital vertebra”. This tubercle is not comparable from a phylogenetic point of view, to the medial condyle of birds and reptiles, as it does not participate as an articular surface in cranio-vertebral joint. Position of this tubercle may be related to traumatic medullar lesions of occipito-vertebral region.
