Unilateral demonstration of the atlas in ipsilateral maxillary alveolar bone destruction

In conventional sinus films in occipito-frontal projection, the atlas is superimposed on the maxillary alveolar processes. If destruction of the alveolar process is present, the atlas-half on the affected side may be unusually clearly demonstrated. The value of this 'unilateral demonstration of the atlas' was confirmed by comparing a group of 20 patients with alveolar process destruction with two groups of 50 patients, one reported as normal and another with mucosal thickening, fluid levels or entirely dense sinuses.