A high-arched palate (also termed high-vaulted palate) is where the palate is unusually high and narrow. It is usually a developmental feature that may occur in isolation or in association with a number of conditions. It may also be an acquired condition caused by chronic thumb-sucking. High-arched palate may cause narrowed airway and sleep disordered breathing.
Example conditions which may be associated with high-arched palate include:
References
High-arched palate Wikipedia(Text) CC BY-SA