Temporomandibular Disorder (TMD) — When You Cannot Open Your Mouth Wide
Table of Contents
What is temporomandibular disorder (TMD)?
Temporomandibular disorder (TMD) is an umbrella term for a group of conditions that cause pain and dysfunction in the temporomandibular joint (TMJ) and the surrounding masticatory muscles. About 20–30% of Korean adults experience at least one TMD symptom, and it is especially common in women in their 20s to 40s. Pain occurs when opening the mouth or chewing, and severe cases make even eating difficult.
Anterior disc displacement and limited mouth opening
Inside the TMJ there is a fibrocartilage structure called the articular disc that allows the mandibular condyle to move smoothly. When this disc is pushed forward from its normal position (anterior displacement), the condyle catches on the disc during opening, limiting how wide the mouth can open. Normal maximum mouth opening is about three finger-widths (40–50 mm), but with disc displacement it can drop below two finger-widths (25–30 mm).
Disc displacement with vs. without reduction
- Disc displacement with reduction: During opening, the disc returns to its proper position, producing a 'click' sound. Mouth opening is only mildly limited, but the clicking recurs.
- Disc displacement without reduction: The disc fails to return, severely restricting mouth opening. In the acute phase, a sudden inability to open the mouth — known as closed lock — develops.
Korean medicine treatment — combined acupuncture, chuna, and herbal medicine
- Acupuncture at Xiaguan (ST7) and Jiache (ST6): Needling Xiaguan directly above the TMJ and Jiache over the masseter improves blood flow around the joint and reduces pain. Adding electroacupuncture (2 Hz) further promotes endorphin release.
- TMJ chuna (joint mobilization): The Korean medicine doctor gently distracts and glides the mandible to widen the joint space, creating conditions for the anteriorly displaced disc to return. It produces immediate improvement in mouth opening for acute closed lock.
- Herbal medicine: Modified Soshiho-tang (Xiaochaihu-tang) regulates liver and gallbladder function, while Jakyakgamcho-tang (Shaoyao Gancao Tang) relieves spasm of the masticatory muscles.
Self-care
Avoid hard foods (nuts, squid) and excessive mouth opening (large hamburgers, yawning), and correct unilateral chewing habits. Applying a warm compress to the TMJ area for 15–20 minutes helps relax the muscles. Perform active mouth-opening exercises, gently moving the jaw side to side, three to five times a day.