What is the role of temporomandibular joint (TMJ) in trismus intervention?

The joint in the jaw, known as the temporomandibular joint (TMJ), is a special joint that allows for a variety of movements. We need these movements to complete the jobs of chewing, talking, opening our mouth to yaw and put a spoon in and brush our teeth. The movements of the TMJ joint include the following: 

1. Hinge Movement: Think of a the hinge of a trunk, the purpose is open and close. The TMJ serves as a hinge joint. The movement of opening is called called jaw depression (opening) while (closing) is jaw elevation. Muscles will aide in these activities as well however, the joint needs to be fully functional for optimal mouth opening and closing. 

2. Protrude and Retract: During activities of oral care, dental work or chewing the jaw may need to move forward (protrusion) or backwards (retraction). 

3. Lateralization Movement: The jaw is able to move side-to-side or laterally. We measure this as  jaw lateral excursion. Functionality allows us to move food, chew gum and push the bolus to opposite sides of the mouth. 

4. Combined Movements: A rotary chew is the most effective and latest developed chew pattern. The jaw joint utilizes a combination of movements and motions to masticate bolus into a size that we are safely able to swallow. This sequence of activities is performed through combining protrusion, retraction, lateralization, elevation and depression! 

Muscles aide in each of these movements. Your therapist will assess a muscular dysfunction versus a jaw joint dysfunction. It is imperative to differentiate the two as one can be improved through physiotherapy or speech pathology and the other requires medical intervention. During our ARKJ trismus intervention course we teach therapist to differentiate these disorders for optimal healing and recovery! 

This article was written by Lauren Meffen MA CCC/SLP, CLT with the help of chat.open.ai.

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