Condition in which the cheeks of the mouth expand greatly with pressure, such as with the famous bebop trumpet player Dizzy Gillespie. Dizzy played his horn incorrectly for some 50 years, letting his cheeks expand when he played, instead of keeping them taut as is considered correct. This was mostly due to his general lack of early musical education. Although Mr. Gillespie was able to create a surprisingly good sound using this form, over time it left his cheeks saggy and loose. A doctor who wanted to use his image in a book named the condition after him. With Gillespie pouches, the cheeks inflate to look almost like balloons. Besides brass players, Gillespie pouches may be found among some balloon artists, who regularly apply great pressure to their cheeks while inflating balloons.