The incidence and nature of fibrous continuity between the sphenomandibular ligament and the anterior malleolar ligament of the middle ear.

The purpose of this study was to determine the structural interrelationship between the temporomandibular joint (TMJ) and the middle ear, in terms of fibrous continuity between the sphenomandibular ligament (SML) of the mandible and the anterior malleolar ligament (AML) of the middle ear. Thirty-seven specimens of the TMJ and middle ear were obtained from adult human cadavers. The temporal bone, petrotympanic fissure, mandibular fossa, and middle ear were dissected en bloc, fixed, sectioned, stained, and observed microscopically. Of the 37 specimens, 67.6% had a continuity of the SML through the fissure passing near the malleus of the middle ear. The AML was present at the fissure in 64.9% of the specimens, with 58.3% passing through and not stopping at the fissure. Results indicated a fibrous continuity between the SML and the AML. Structural differences between the two ligaments were also noted. The SML contained randomly arranged fibrous connective tissue with numerous interposed blood vessels. The AML had a smooth arrangement of fibers within the connective tissue, and few blood vessels were apparent. The clear anatomic relationship observed strongly supports the contention of a functional interrelationship between the TMJ and the middle ear.