The petrotympanic fissure: a link connecting the tympanic cavity and the temporomandibular joint.

Morphological traits of the petrotympanic fissure, a soft tissue containing connection between the middle ear and the temporomandibular joint, are described. The description is based on sagittal histological sections of 67 petrous bones with the proximal part of the mandible. The morphological pattern of the soft tissues within the petrotympanic fissure does not, other than in association with exceptional anatomic conditions, support the opinion that forces may be transferred from the joint to the middle ear. The petrotympanic fissure is mainly to be looked upon as a reminder of earlier evolutionary stages. It may also call attention to a developmentally caused special neurological pattern where the innervation of chewing muscles and some middle ear and pharyngeal muscles are closely related to each other. Taking the developmental facts into account in the clinical situation, it may not be so confusing that a primary pathological stimulus in the chewing apparatus and its muscles may, secondarily, manifest itself as ear symptoms. This symptomatology is known as the "otomandibular syndrome."