Abstract
The external auditory canal (EAC) consists of a bony part and a cartilaginous part. Foramen tympanicum (Huschke's foramen) can be observed sometimes in the bony part (tympanic bone) as a developmental abnormality. However, it is rare in clinical dentistry. In this study we report a 66-year-old female patient with chief complaints of trismus and temporomandibular joint (TMJ) pain in December 2009. She had visited our ENT (Ear, Nose, Throat) clinic the previous year for resonant vibration of voice. Herniation of the posterior tissue of TMJ disc into EAC was observed; the degree of herniation was associated with opening/closing of the mouth, so she was referred to our clinic. The mouth opening without pain was 22 mm at the initial examination, and that with pain was 30 mm. On panoramic radiograph, right TMJ arthrosis deformity was suspected. On CT, a bone defect of approximately 5.5 mm in diameter was observed with herniation of the posterior tissue of TMJ disc. From these findings, a diagnosis of foramen tympanicum with TMJ arthrosis was made. There was no association with the chief complaints of trismus and TMJ pain. At present, her trismus without pain is 35 mm, and observation has been made with mouth-opening training.
