Review of the Tanaka Ligament in the Temporomandibular Joint. Analyzing its Scientific Validity

Abstract

SUMMARY:The temporomandibular joint (TMJ) is composed of bony structures, cartilage, capsule, articular disc, synovial membrane and ligaments. Some authors consider the "Tanaka ligament" described in the 1980s by Terry Tanaka as an intra-capsular ligament of the TMJ that unites medially the articular disc and mandibular fossa. The aim of the present study was to analyze the use of the term "Tanaka ligament" in the literature evaluating the scientific support of its existence. A literature review was carried out under the terms "Tanaka Ligament [AND] TMJ" and "Ligamento Tanaka [AND] ATM" (Spanish and Portuguese) in the search engines: MEDLINEPubmed, Science Direct, Google Scholar, LILACS-Bireme and SciELO. Scientific articles and theses were considered in English, Spanish and Portuguese. A total of 1,355 studies were found, summing up the results of all the search engines, of which 8 studies (5 articles and 3 theses) were selected after applying inclusion and exclusion criteria, selection by title, abstract and content. Most of these studies were discarded because they had contents related to the TMJ and/or ligaments wherein an author used the surname "Tanaka", that were not related to the Tanaka ligament. Among the 8 selected studies, 6 of them cite text books, 1 cites a video published by Terry Tanaka and 1 cites a thesis. Most of these textbooks cited also refer to videos by Terry Tanaka and his books. Moreover, most of the anatomical literature does not consider this ligament as an individualized structure. Although there are descriptions of Tanaka's ligament in textbooks, the scientific support of its existence is based only on videos and texts by Terry Tanaka. The dissemination of knowledge associated with this ligament must be cautious, as there is a need for further morphological and functional studies to confirm its existence.

Dynamic Weight-bearing Magnetic Resonance in the Clinical Diagnosis of Internal Temporomandibular Joint Disorders

“…Other important components are the joint capsule, the synovial membrane, and some ligaments. [18][19][20][21] In the back is highly vascularized tissue critical for the functional balance of the TMJ, called the bilaminar area 22,23 (►Fig. 1).…”

“…They can be intracapsular, such as the medial and lateral ones, or extracapsular, such as the temporomandibular (lateral), sphenomandibular, and stylomandibular ligaments. 21 Some authors recently discussed another intracapsular ligament described for the first time by Terry Tanaka in 1984 and then named for him. 21 This ligament can be considered part of the medial ligament, and its function could be the connection of the articular disk to the mandibular fossa; its endings blend into the insertion fibers of the tensor tympani and the tensor veli tendons.…”

“…21 Some authors recently discussed another intracapsular ligament described for the first time by Terry Tanaka in 1984 and then named for him. 21 This ligament can be considered part of the medial ligament, and its function could be the connection of the articular disk to the mandibular fossa; its endings blend into the insertion fibers of the tensor tympani and the tensor veli tendons. During swallowing, the contraction of the medial pterygoid muscle, which stabilizes the dental arches, occurs along with the contraction of the tensor tympani and internal and external peristaphylin muscles.…”