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Restricted Jaw Movement (Trismus)

Having difficulty opening your mouth fully is called trismus. Trismus is a common side-effect of head and neck cancer treatment (surgery or radiation).


  • A normal mouth opening is 35mm and larger.  This is measured between your front teeth (incisors)
  • Trismus is defined as any mouth opening smaller than 35mm
  • Trismus can impact your ability to eat, speak, receive good oral care and dental check-ups, yawn, laugh and kiss
  • Most people can place their three fingers side by side between their upper and lower teeth. This is a quick check that you can do to see if you might need further assessment
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hat Can You Do?
  • A Speech-Language Pathologist can help assess and create a customized treatment plan to improve your jaw movement

  • Speak to your doctor if you suspect that your ability to open your mouth widely is reduced

  • It is important to seek professional advice before trying to treat your trismus. Stretching too much too soon can cause further damage
SOURCE: Restricted Jaw Movement (Trismus) ( )
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