[Panoramic image of the hard palate and the nasal floor]

The author investigated the origin of two linear radiopaque images superimposed upon the lower part of the maxillary antra and nasal cavity. The obtained results were as follows: 1. The upper blurred image was not the ghost image of the lower sharp image. 2. The upper image was not formed by the horizontal plate of palatine bone and the lower image was not formed by the palatal process of maxilla. 3. The upper image and lower image seemed to be formed by the junction of the nasal septum to the hard palate and by the junction of the maxillary antrum and the hard palate respectively. But there were some unidentified structures which formed these two images.