A Direct Anatomical Study of the Morphology and Functionality of Disco-malleolar and Anterior Malleolar Ligaments

The disco-malleolar and anterior malleolar ligaments are common to the middle ear, the temporomandibular joint and the jaw, all of them sharing a common embryological origin; these ligaments' morphometric and functional aspects were studied in 23 temporal bones. Experimental design: The epitympanum roof and the temporomandibular joint roof were elevated by micro-dissection of the middle cranial fossa, exposing both disco-malleolar and anterior malleolar ligaments and their association with the malleus, the temporomandibular joint disc and the mandibular lingula. Principal observations: Both ligaments start in the malleus and take anterior and divergent routes towards the temporomandibular joint and lingula, passing through Huguier's canal. The disco-malleolar and anterior malleolar ligaments' mean lengths were 6.88 mm (SD 0.81) and 4.22mm (SD 1.17), respectively, no statistically significant difference being revealed between the sides. Temporomandibular joint disc traction was applied for verifying malleus mobility; malleus movement was observed when applying disco-malleolar traction in 30.5% of the samples. Correlation was observed between malleus movement and disco-malleolar length (R2=-0.499, p<0.05). Both ligaments common to the stomatognathic system and middle ear were present in all specimens. Conclusions: There was an anatomical and functional relationship between human TMJ and the middle ear.