Do you all remember the FORD PINTO from about 1971? Now you might be asking what does the Ford Pinto have to do with Tinnitus, ringing in the ear, aural symptoms, and TMD or TMJ pain?? Well, nothing…. except to discuss a little quick anatomy today of a ligamentous attachment from the Temporomandibular Joint to the Malleus bone of the inner ear, and you guessed it, the name of that ligament is the Pinto Ligament, coined by Dr. Pinto who discovered it in the early 1960s if I am correct and in 1962 published a paper entitled: A new structure related to the temporomandibular joint and middle ear. (J Prosthet Dent. 1962;12:95-103.)

Discomalleolar Ligament Anatomy. A connection of fibrous tissue between the TMJ and the middle ear passing through the petrotympanic fissure was described early. In a histologic study of 20 TMJ specimens, Pinto observed “a tiny ligament, connecting the neck and anterior process of the malleus to the medioposterosuperior part of the capsule, the interarticular disc, and the sphenomandibular ligament.” The consistency and especially the functional importance of this observation have been much debated,—

In this Study, Rowicki T, Zakrzewska J. A study of the discomalleolar ligament in the adult human. Folia Morphol (Warsz). 2006 May;65(2):121-5, Fourteen adult human temporomandibular joint and tympanic cavity specimens were examined with the use of an endoscope and then by gross dissection with the superior approach and with the use of the operating microscope. Endoscopic visualization showed in four cases a band of tissue in the upper temporomandibular joint compartment, known as Pinto’s ligament. The dissections exposed a discomalleolar ligament in 11 specimens. They were able to identify two main types of this ligament on the basis of its shape. The discomalleolar ligament was either triangular in shape, as in the first group of seven specimens, or longitudinal in shape, as in the second group of four specimens. They observed that tension applied to the discomalleolar ligament resulted in the movement of the malleus in three specimens.

B

Note that most of the fibers (arrowheads) arising from the posteromedial aspect of the articular disc and capsule do not reach the malleus. The discomalleolar ligament is contiguous with the anterior malleolar ligament (DML/AML) (A). When these fibers were elevated with tweezers a bundle of fibers (arrowheads) was observed detaching from the DML/AML and joining the articular disc and capsule just beneath the petrotympanic fissure (B); HM — head of malleus; I — incus; S — stapes; TM — tympanic membrane; CT — chorda tympani nerve; AD — articular disc.

Rowicki T, Zakrzewska J. A study of the discomalleolar ligament in the adult human. Folia Morphol (Warsz). 2006 May;65(2):121-5.

Photographs showing the topography of the discomallear ligament in the superior aspect of the right middle cranial fossa. In all specimens, the wedge-shaped DML was attached to the disk and capsule of the TMJ (A, B). In addition, the medial margin of the DML was extended and attached to the anteromedial region of the petrotympanic fissure (B). M, malleus; DML, discomallear ligament; CT, chorda tympani; PTF, petrotympanic fissure; cap, capsule of the TMJ

Kim, H.J., Jung, H.S., Kwak, H.H. et al. The discomallear ligament and the anterior ligament of malleus: An anatomic study in human adults and fetuses. Surg Radiol Anat 26, 39–45 (2004).

The discomallear ligament and anterior ligament of malleus in the superomedial aspect of the right middle cranial fossa. The DML and ALM are separated by the bony ridge in Huguier’s canal within the petrotympanic fissure (dotted area). Two distinct superior (white arrow) and inferior (black arrow) lamellae of the ALM were observed. The superior lamella ran from the head of malleus to the anteromedial margin of the petrotympanic fissure. The inferior lamella pierced through the petrotympanic fissure and became continuous with the sphenomandibular ligament. M, malleus; DML, discomallear ligament; ALM, anterior ligament of malleus; CT, chorda tympani

Kim, H.J., Jung, H.S., Kwak, H.H. et al. The discomallear ligament and the anterior ligament of malleus: An anatomic study in human adults and fetuses. Surg Radiol Anat 26, 39–45 (2004).

The clinical importance of the DML and ALM has been reported, with a focus on the aural symptoms that result from middle ear damage associated with excessive anterior disc displacement or jaw movement. In particular, some investigators observed mobility of the malleus as the DML is overstretched.

Mobility of the malleus in response to an overstretched ALM has been demonstrated by some investigators. In this study, responsive movement of the malleus was detected in five specimens when the ALM was overstretched. Based on these results, they carefully predicted that middle ear symptoms might be caused by the overstretched ALM during jaw movement. However, because ligamentous movements occur more freely in specimens when surrounding bony structures are removed by dissection, it is hard to conclude that movement of the malleus may be caused by the ALM, based on only anatomical observations.

Summarizing the results of this study, they concluded that in all adult specimens the DML and ALM were definitive anatomical structures attached to the malleus, not degenerated forms or traces remaining after development. In addition, they found that the DML and ALM are topographically two independent ligamentous structures located in Huguier’s canal. Finally, in some cases, mobility of the malleus was detected when tension was applied directly to the ALM, a ligamentous structure continuous with the SML, thereby demonstrating the clinical importance of the ALM in cases with aural symptoms. The most commonly reported aural symptoms in TMD patients are otalgia, tinnitus, vertigo and subjective hearing loss.

Kim, H.J., Jung, H.S., Kwak, H.H. et al. The discomallear ligament and the anterior ligament of malleus: An anatomic study in human adults and fetuses. Surg Radiol Anat 26, 39–45 (2004).

So the beat goes on, more research needs to be done, not sure we have a definitive answer one way or another, but the possibility exists.

Like so much in the world of TMD, we know what we know, and what we don’t know, we don’t know!