We report a patient with jaw trismus demonstrating Square-Mandible face.
Clinically, the patient had a square face with prominent masseter muscles and mandibular angles. The interincisal opening was 26mm, with limited lateral and anteroposterior mobility.
The clinical diagnosis was restricted mouth opening due to bilateral hyperplasia of the masseter muscle aponeuorses. Masseter muscle myotomy with aponeurectomy was performed bilaterally by an intraoral approach. Mouth opening improved to 40mm after incision of the aponeuroses.
An examination of the patient one year after surgery demonstrated an interincisal opening of 37mm without strain.
