These are very hard, bony growths in the roof of the mouth. They start out small, but can become quite large over time. Sometimes they can interfere with the construction of an upper denture. Removal of these can be complicated by their proximity to the nasal cavity. Upon occasion they are "pneumatized" meaning that the nasal cavity may extend into the torus itself.
These start out small, but can grow quite large over time. Most of the time they stop growing at some point. They are very hard, bony growths in the roof of the mouth, and are easily diagnosed simply by feeling them with a finger.