You are on call one weekend when your on-call mobile phone rings and you are requested to re-attend and reopen your surgery urgently. You are advised by the wife of one of your patients that he has been struck in the face playing football and he cannot close his mouth. She said he has got ‘lock jaw’. She says that she is on her way to the surgery and will meet you there.

As you re-attend the practice your patient and his wife are driving into the car park. He is still dressed in his football kit and is in obvious pain. He is holding a towel to his mouth as he is dribbling saliva. There is no bleeding.

You reopen the surgery and with the assistance of his wife take a history. It would appear that Steven had been trying to head the ball. He had leapt up but had clashed heads with a defender. He remembers that he had his mouth open at the time and the defender’s head hit him on the right side of his chin. He was stunned but not rendered unconscious and fell to the ground. He was immediately aware of acute pain in both right and left TMJs and also aware that he could not close his mouth. He felt that any attempt at jaw movement was acutely painful. He was also aware of the fact that his mandible had slewed across to the left side and that a depression had appeared in front of his right ear.

It was apparent during history taking that he could not speak comfortably or clearly and was relying on writing notes and his wife interpreting his account of events. He was also not able to swallow comfortably and was dribbling saliva. He was in obvious and increasing pain and his wife estimated that it was less than half an hour since the trauma occurred. Steven and his family were new patients to your practice and you had only seen him once before. He had no relevant medical history and he had a restoration and caries-free mouth. His oral hygiene was excellent.

Examination

On extraoral examination, there were no contusions, abrasions or lacerations on Steven’s face. There was, however, a red area over the body of the mandible, in the canine region on the right side, and this would appear to correspond with the area that his opponent’s head struck. Steven’s mouth was stuck open at approximately 25 mm. When being asked to move his mandible, any movement was obviously painful and he could move to increase his opening by only 3 or 4 mm. He was unable to close his mouth any further and lateral movements were too painful for him to perform, although he did volunteer that even if the pain had not been there he didn’t think he would be able to move his jaw sideways. His chin was obviously deviated to the left side.

Examination of the origin of the masseter muscles was extremely uncomfortable and you were not sure whether you were eliciting pain from the muscle itself or by palpating in the area around the TMJs. There was temporalis tenderness of the vertical fibres in the anterior part of the temple on the right side. Tenderness was also apparent on the left side but less so. You were unable to examine the lateral pterygoid muscles against resistance because he could not stand any pressure under his chin as a result of pain and could not exert any lateral pressure.

Radiographs

You had facilities to take only intraoral radiographs but could not do this because he could neither open nor close his mouth. In addition you decided that these would be of no diagnostic value.

Other Special Tests

You did feel that an extra oral radiograph of his temporomandibular joints such as a transcranial oblique lateral (TOL) view would be of value but the practice that you normally refer your patients to for extraoral radiographs was closed and there was no local hospital near enough for you to refer him.

Likely Diagnoses