Minh

My RO, ENT and prothodontist all said that if i can't fit three fingers into my mouth, I have trismus. The OCF write up on Trismus also gives this test
[quote]A simple test for trismus

Trismus tends to develop slowly. In some patients, it progresses so slowly that they may not notice it until they can only open their mouth to 20mm or less. Treatment that begins early in the progression of the condition is likely to be more effective, and easier on the patient. Because of this, it is important to be proactive in looking for early signs of trismus. One simple test is the 'three finger test'. Ask the patient to insert three fingers into the mouth. If all three fingers fit between the central incisors, mouth opening is considered functional. If less than three fingers can be inserted, restriction is likely. [/quote]

The full OCF text is here with simple stretches. Trismus OCF

Luckily you can start stretching exercises without a prescription or doctor although after the surgery and recurrence and second radiation TX, mine got so bad I did need a Therabite which I still use daily.
Charm