Evaluation of lateral pterygoid muscle symptoms using a common palpation technique and a method of functional manipulation

A critical overview of the current myofascial pain literature - September 2016

This edition of the overview of the current myofascial pain literature includes 24 studies, case reports and systematic and narrative reviews. Surprisingly, five of the 24 papers were difficult to read and interpret mostly because of a poor mastery of the English language. It is somewhat surprising that journal editors and reviewers would accept papers that are needlessly difficult to read and not direct the authors to language services or others who could improve the quality of the writings. Of course, it is exciting that researchers and clinicians from all over the world continue to focus on myofascial pain and attempt to shed new light on the complexity of the problem to improve the clinical decision-making process and eventually clinical approaches and outcomes. There were no new papers on manual therapies, but many focused on dry needling.

Palpation of the lateral pterygoid region in TMD--where is the evidence?

OBJECTIVE

Palpation of the lower head of the lateral pterygoid muscle is included in many study protocols and examination schemes of the masticatory system. The aim of this investigation was to search the medical/dental literature to find evidence for the validity and reliability of this diagnostic procedure.

METHODS

A systematic search was carried out using different electronic databases (Medline Ovid, PubMed, Cochrane Library, Embase, Current Contents Connect, Science Citation Index, Web of Science, Japana Centra Revuo Medicina), supplemented by handsearch in selected journals and by examination of the bibliographies of the identified articles.

RESULTS

VALIDITY

As far as the palpability of the inferior head of the lateral pterygoid muscle is concerned, five publications representing four studies could be identified. According to these investigations, the lateral pterygoid muscle is practically inaccessible for intraoral palpation due to topographical and anatomical reasons. Other anatomical structures, such as the superficial head of the medial pterygoid muscle, may be palpated instead in this region. Reliability: Determination of the palpability of the lateral pterygoid muscle is characterized by poor interexaminer agreement. Studies investigating the presence of pain in response to palpation of the lateral pterygoid area revealed a moderate intra- and interindividual reliability. Because of the tenderness of the lateral pterygoid region even among healthy subjects, positive findings may lead to wrong conclusions with regard to the need of treatment.

CONCLUSIONS

Considering the lack of validity and reliability associated with the palpation of the lateral pterygoid area, this diagnostic procedure should be discarded.

Clinical anatomy and palpability of the inferior lateral pterygoid muscle

STATEMENT OF PROBLEM

The intraoral palpation technique of the inferior belly of the inferior lateral pterygoid (ILP) muscle is a standard diagnostic examination method for temporomandibular joint dysfunction syndrome, although different studies have revealed inconsistent results.

PURPOSE

This study assessed the feasibility of the ILP muscle palpation by a simulated clinical setting.

MATERIAL AND METHODS

Three dentists performed a bilateral palpation of the ILP muscle in 53 fresh and unfixed human cadavers and decided whether the muscle was palpable or unpalpable. In a second step, it was observed through the dissected infratemporal fossa, whether the examiner's finger did or did not touch the ILP muscle by simulating the performed palpation. Palpatory findings were supplemented by 1-dimensional measurements for determination of topographic relations of the ILP muscle within the infratemporal fossa. For statistical analysis, sensitivity, specificity, and negative and positive predictive values of the palpation technique were calculated. Interexaminer agreement was estimated with the kappa value.

RESULTS

In 86 of 106 dissected specimens, a superficial fascicle of the medial pterygoid muscle was found in direct proximity to the ILP muscle. In these cases, a residual distance of 7.8 +/- 3.2 mm remained between the ILP muscle and buccinator fascia indented by the tip of the examiner's finger. In 10 of 20 specimens with an absent superficial fascicle, the finger was able to reach the ILP muscle.

CONCLUSION

It is recommended that the ILP muscle palpation technique should no longer be considered as a standard clinical procedure because it is nearly impossible to palpate the ILP muscle anatomically and because the risk of false-positive findings (by palpation of the medial pterygoid muscle) is high.