To investigate the prevalence of ponticulus posticus (PP) in Uruguay, as well as its anatomoclinic characteristics, we used dry bone pieces and CT scans of the first cervical vertebrae. Seventy-seven dry bone pieces from Facultad de Medicina de la Universidad de la República (Montevideo, Uruguay) and UCLAEH (Maldonado, Uruguay) were analyzed macroscopically. Posteriorly, 55 CT scans of the cervico-occipital junction were analyzed with 3D reconstruction.
Out of the 77 analyzed atlases, 30 presented PP (38.9%), 12 were bilateral cases and 18 were unilateral. Out of the 42 bony bridges, 20 were situated on the right (47.6%) and the other 22 (52.4%) on the left, 14 were complete (33.3%) and 28 were incomplete (66.7%). The analyzed CT corresponded to 25 men and 30 women, with a mean age of 49 years. Nineteen pieces presented PP (34.5%), 11 were bilateral cases and 8 were unilateral. This totalize 30 bridges, 12 (40.0%) were situated on the right and the other 18 (60.0%) on the left, 15 (50.0%) were complete PP and 15 (50.0%) were incomplete. In the CT analysis, the male gender showed statistical association with PP presence (p=0.013). PP is an anatomical variation with high prevalence in our population, usually overlooked if systematic search is not performed. Its great surgical and clinical implications make it of great interest to know its presence and characteristics.