Is the posterior belly of the digastric muscle palpable? A qualitative systematic review of the literature

Abstract

Palpation of the posterior belly of the digastric muscle in the postmandibular region is included in many study protocols and examination schemes of the masticatory system. The aim of the present investigation was to systematically search the dental/medical literature to find evidence for the palpability of this muscle. In August 2004, a systematic search was carried out using different electronic databases (PubMed, Cochrane Library, Web of Science, Japana Centra Revuo Medicina, MedPilot, Latin American and Caribbean Health Sciences, and three on-line databases of dental journals not listed currently in Medline), supplemented by manual search in the Austrian journal Stomatologie. Additional manual searches were carried out in the Journal of Orofacial Pain and Journal of Dental Research to identify pertinent abstracts of scientific congresses. One relevant hit was found in the Japanese database. The manual search showed one pertinent congress abstract. In both publications, the authors concluded that due to anatomical reasons the posterior belly of the digastric muscle was not palpable. Hence, evidence is lacking that the posterior digastric muscle is accessible to palpation. Because the postmandibular region is usually tender upon palpation, a high incidence of positive findings can be expected even among healthy subjects. This may lead to wrong clinical judgments, possibly provoking unnecessary diagnostic and therapeutic measures.

Reliability and Validity of the Diagnostic Criteria for Temporomandibular Disorders Axis I in Clinical and Research Settings: A Critical Appraisal

“…Surprisingly, palpation of supplemental muscle sites that are anatomically not accessible is still endorsed in the DC/TMD protocol and includes the amount of palpation pressure 21 despite the evidence for the inaccessibility of these muscles, as is the case for the lateral pterygoid muscle 22 and the posterior digastric muscle. 23 In the new protocol, pressure in the posterior mandibular region is now carried out medially at the posterior aspect of the mandibular angle and at the medial wall of the mandible, probably aiming at the attachment of the medial pterygoid muscle. Yet, the region behind the posterior aspect of the mandibular ramus contains many structures that may easily produce pain when pressure is applied even among symptom-free individuals, which may include non-TMD patients.…”

Temporomandibular disorders assessment: medicolegal considerations in the evidence‐based era

“…Systematic reviews on the diagnostic approach to TMD covered the arguments of the accuracy of several diagnostic tools, viz., magnetic resonance ( n = 2) (86, 87), imaging techniques ( n = 1) (88), ultrasonography ( n = 1) (89), clinical diagnosis ( n = 2) (90, 91), electronic devices ( n = 2) (65, 68), posturography ( n = 1) (69) (Table 1).…”

“…When compared with magnetic resonance findings, accuracy of clinical diagnosis of disc displacement with reduction ranged between 79% and 90% among different studies (113, 115, 116), while it ranged between 65% and 89% for cases of disc displacement without reduction (113–115, 117), and it is about 80% for TMJ pain (100). As for muscle disorders, the main symptom of which is pain, the absence of a gold standard instrument for pain rating makes clinical evaluation itself the most useful diagnostic approach (118), even if a low intra‐ and inter‐examiner reliability of findings from palpation of some muscle sites, viz., digastrics and lateral pterygoid areas, have been reported (90, 91).…”

Morphometry of the Digastric Ridge and Its Significance for Mastoid Surgeries—A Cadaveric Study

“…The DR corresponds externally to the digastric groove at the medial aspect of the mastoid process, from which the posterior belly of digastric muscle originates. 1,2 The DR divides the mastoid tip cells into 2 groups, the lateral and medial (subsinus cells at the sigmoid mastoid terminalis) tip cells. 3,4 Clinically, the DR is an important landmark in the identification of the facial nerve (FN) and sigmoid sinus (SS).…”