Schobinger cites a similar instance, due to loosening of the frenum.
Analogous to the foregoing phenomenon is the habit of "tongue sucking." Morris mentions a young lady of fifteen who spontaneously dislocated her jaw, owing indirectly to this habit.

Morris says that from infancy the patient was addicted to this habit, which was so audible as to be heard in all parts of the room.

The continued action of the pterygoid muscles had so preternaturally loosened the ligaments and muscular structures supporting the joint as to render them unable to resist the violent action of "tongue sucking" even during sleep.
Injuries to the Tongue .-- Hobbs describes a man of twenty-three who, while working, had a habit of protruding his tongue.

One day he was hit under the chin by the chain of a crane on a pier, his upper teeth inflicting a wound two inches deep, three inches from the tip, and dividing the entire structure of the tongue except the arteries.

The edges of the wound were brought into apposition by sutures, and after the removal of the latter perfect union and complete restoration of the sensation of taste ensued.