Spontaneous temporomandibular joint herniation into the external auditory canal through a persistent foramen tympanicum (Huschke): radiographic features.

Persistent foramen tympanicum (Huschke) is an anatomical variation located in the anteroinferior portion of the external auditory canal. We present a case of symptomatic temporomandibular joint (TMJ) herniation into the external auditory canal though an enlarged osseous defect. The herniated retrodiscal TMJ tissue moved backward when the patient's mouth was closed, and forward, when opened. Magnetic resonance imaging findings were useful for differentiating TMJ herniation from salivary fistula caused by an ectopic salivary gland.