The canine jaw‐ear connection: The malleomandibular and tympanomandibular ligaments

Abstract

In the human, two ligaments derived from the first embryonic pharyngeal (branchial) arch that unite the mandible and temporomandibular joint (TMJ) with the middle ear have been identified as the discomalleolar ligament (DML) and sphenomandibular ligament (SML), also known as the malleomandibular ligament (MML), anterior ligament of the malleus (AML), and tympanomandibular ligament (TML). Neither of these structures has been previously described in the dog. The homologue of the human sphenomandibular ligament (SML) exists in the dog and is represented as a fibrous remnant of Meckel's cartilage. In the newborn puppy, the ligament is a true malleomandibular ligament (MML), extending from the medial mandible to the rostral process of the malleus with no intermittent attachments. In the adult dog, the ligament is entrapped within a bony passageway, likely due to the development and ossification of the tympanic bulla, making it difficult to grossly view the complete course of the ligament. The majority of the ligamentous fibers attach near the tympanic bulla in the adult dog, thus this portion of the ligament has been named the tympanomandibular ligament (TML). Those fibers of the ligament not attaching near the tympanic bulla appear to continue through a canal, located between the tympanic annulus and the surrounding tympanic bone, to become continuous with a connective tissue sheet within the cavity of the middle ear that has attachments to the malleus and incus. Tension on the adult canine TML did not result in movement of the malleus. Anat Rec, 297:876-891, 2014. V C 2014 Wiley Periodicals, Inc.

The development of the mammalian outer and middle ear

“…The separation process is complete by P3, and the remaining Meckel's cartilage continues to breakdown as part of its presumed transformation into the malleomandibular ligament, the proximal portion of which is the anterior ligament of the malleus (Anthwal et al. ; Stevens‐Sparks & Strain, ; Fig. ).…”

“…In mice, separation of the malleus and the mandible occurs from P1 by the onset of the breakdown of the neighbouring Meckel's cartilage. The separation process is complete by P3, and the remaining Meckel's cartilage continues to breakdown as part of its presumed transformation into the malleomandibular ligament, the proximal portion of which is the anterior ligament of the malleus (Anthwal et al 2013;Stevens-Sparks & Strain, 2014;Fig. 6).…”

Comparative Analysis of Laser and Non-Laser Stapes Surgeries

“…In the laser group, such situations would never occur. Similarly, in dealing with the cases with anterior malleolar ligament ossification, vertigo, and follow-up problems caused by non-laser-assisted malleus processing induced by enormous displacement and shaking of the stapes and piston would be extremely serious [17,18] .…”

Duplication of the Sphenomandibular Ligament

“…This wide attachment seems similar Ouchi’s type III classification, although the origin of this SML in our case had two heads. Interestingly, the older term for the SML was the tympanomandibular ligament or malleolomandibular ligament [ 2 , 7 ] as the ligament might have continuity with the malleus of the middle ear. In the present case, however, the posterior part of the SML was only attached to the surface of the mandibular fossa of the temporal bone.…”