[Variants and developmental anomalies of the odontoid process of the axis]

Clinical and X-ray examination of 140 persons demonstrated a wide range of developmental disorders of the odontoid process, from neglible deviations from the average normal structure to total absence of the process. From the pathogenetic standpoints, some of the variants may be characterized as possessing normal structural features, others are developmental anomalies and defects which call for suboccipital decompression, laminectomy for freeing the compressed bulbarspinal parts of the brain or stabilization of the disturbed craniovertebral relationship.