Dislocation of the temporomandibular joint

Japanese: 顎関節脱臼 - がくかんせつだっきゅう（英語表記）Dislocation of the temporomandibular joint

What is the disease?

This is a condition commonly referred to as "the jaw being dislocated." However, it is more accurate to say that the jaw is not dislocated, but rather cannot be put back in place on its own.

When opening your mouth, it forms the jaw joint. Mandible ( Science Tips ) of Mandibular condyle ( Science student ) Rotates forward and downward Glide ( Cool ) When you exercise and yawn loudly, Joint prominence ( Establishment ) If the mandibular head then cannot return to its original position even when trying to close the mouth (it cannot get over the articular eminence backwards), this is called a dislocated temporomandibular joint, and as a result, the mouth cannot be closed.

What is the cause?

For most patients Muscles of Mastication ( Chewing ) This is thought to be the result of fatigue of the muscles that move the jaw and a lack of muscle strength to pull back the lower jaw after it has moved forward and downward when the mouth is opened.

How symptoms manifest

Pain from a dislocated jaw joint, unable to close the mouth on your own after opening the mouth wide, Drooling ( Ryuzen ) (drooling) is observed. Also, the jaw joint area (the area in front of the ear) on the dislocated side will sink in. It may occur on one side or both sides.

If the injury is not corrected immediately and becomes chronic, Staleness ( Chinkyusei ) The temporomandibular joint becomes dislocated, and it is extremely difficult to reset it to its original position. In addition, a condition in which reduction and re-dislocation occur repeatedly within a short period of time is called habitual temporomandibular joint dislocation.

Testing and diagnosis

Diagnosis is based on the aforementioned clinical symptoms and plain X-ray examination. For chronic or habitual temporomandibular joint dislocations that require surgery, CT scans and other tests are added as part of the preoperative examination.

Treatment methods

If the time lapse after the occurrence is short, it is easy Empty hand ( Toshi ) Reduction is possible. Reduction involves stabilizing the patient's head position, placing the surgeon's thumb on the molar area of the patient's mandible, and pushing down while guiding the patient's mandible backwards. After reduction is complete, the area is fixed with an elastic bandage to prevent re-dislocation, and the patient is instructed to limit jaw movement and observed for several days.

However, in chronic cases, manual reduction may become difficult due to organic changes in the joint structure, and surgery may be required. Also, surgery may eventually be required in cases of habitual temporomandibular joint dislocation.

What to do if you notice symptoms

We recommend that you see an oral surgeon as soon as possible.

Yoshiki Hamada

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

どんな病気か

　一般に「あごが外れた」といわれる病態です。が、実は、外れたのではなく、自力で「もどせなくなった」というほうが正しいのです。

　口をあける際に、顎関節を構成する下顎骨(かがくこつ)の下顎頭(かがくとう)は回転しながら前下方に滑走(かっそう)運動し、大あくびをした時は、関節隆起(かんせつりゅうき)と呼ばれる峠を乗り越えてしまいます。その後、口を閉じようとしても下顎頭が元にもどれない（関節隆起を後方に乗り越えられない）状況を顎関節脱臼と呼び、結果的に口を閉じることができません。