Mouth opening exercises post-radiation therapy in Head and Neck cancer patients

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   May 22, 2023

   Dr. Rushil Tanna, Consultant Physiotherapy, HCG Cancer Centre - Borivall

Mouth opening exercises post-radiation therapy in Head and Neck cancer patients


Radiation therapy is one of the important treatment strategies in the management of head and neck cancer. However, almost all patients undergoing radiation therapy experience one or more side effects, depending on the dose, duration, and frequency of the therapy. Trismus is a complication of radiation therapy characterised by limited mouth-opening ability (less than 35 mm). Several mouth-opening exercises are available that may assist patients in opening their mouths. 

In this article, Dr. Rushil Tanna, a highly skilled onco-physiotherapist from HCG Cancer Centre, Borivali, Mumbai, discusses the possible complications that head and neck cancer patients experience while undergoing radiation therapy, and a few exercises that are helpful in managing them.

Complications of Radiation Therapy in Neck and Head Cancer

Head and neck cancer patients may experience several complications after radiation therapy. These complications may be acute (short-term) or chronic (long-term). Patients may experience acute side effects within 7–10 days after the radiation therapy. These side effects include oral mucositis, dry mouth, and loss of taste. The long-term side effects of radiation therapy in neck and head cancer patients include trismus, radiation caries, and osteoradionecrosis. 

Trismus is a condition in which patients are unable to completely open their mouths due to ionising radiation. The patients may also experience pain that further limits the mouth’s opening.

Patients with trismus are also unable to speak properly, resulting in poor quality of life. It has been found that in most cases, trismus occurs within six months after radiation therapy. Usually, there is a 2-4% reduction in oral opening every month that continues for about nine months. It is thus important to identify the condition at an early stage and prevent the progression of trismus. 

Mouth-Opening Exercises to Manage Trismus

Certain mouth-opening exercises can help manage trismus and improve jaw muscle function. Patients should follow all the instructions of their doctors. The timing of initiating these exercises affects the overall outcomes.

The patients should not make any jerky or rapid movements and easily perform the exercise. They may also perform these exercises in front of a mirror to ensure they are performed correctly. The exercises are:

  • Active stretching exercises: These exercises help stretch the jaw muscles. However, at no point during the exercise should the patients experience pain. If there is pain, shift to gentle stretches. During this exercise, the patient sits or stands upright, opens their mouth as wide as possible, and maintains the position for 10 seconds (Figure 1) Streatch Mouth
  • Passive stretching exercises: This exercise helps in managing trismus pain. In this exercise, the patient puts their thumb on the middle teeth of the upper jaw. Then, the index finger of the other hand is kept on the middle teeth of the lower jaw. The mouth is opened as wide as possible, and the patient must maintain this position for 10 seconds. (Figure 2) This exercise must be repeated 5 times. Passing Streatching
  • Chin tucks: This exercise improves movements and reduces tension by improving neck and shoulder flexibility. The chin is moved towards and touched with the chest during this exercise. The patient then pulls their head back into the normal position (Figure 3). Chin tucks
  • Neck stretch: Neck stretching is also important for maintaining flexibility and improving movement. During this exercise, the patient moves their head forward and backwards (Figure 4). The head is then turned to the right and then to the left (Figure 5). The head is then tilted to the right, so the ears move towards the shoulder (Figure 6). However, the patient should not stretch excessively. Neck stretch Neck stretch 2

By practising these exercises, head and neck cancer patients can improve their jaw muscle function and reduce trismus-related pain and discomfort. If you’re a head and neck cancer patient, talk to your physiotherapist about incorporating these exercises into your daily routine.


In conclusion, head and neck cancer patients who undergo radiation therapy may experience complications such as trismus. However, there are various mouth-opening exercises that can help manage trismus and improve the quality of life for patients. Active and passive stretching exercises, chin tucks, and neck stretches are all effective ways to prevent the progression of trismus. It is important for patients to follow their doctor’s instructions and start exercising early to maintain flexibility and improve movement in the jaw and neck area. With proper care and attention, patients can minimise the negative effects of radiation therapy and maintain a better quality of life.

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