77 - Anatomical Study of the Innervation of the Lateral Pterygoid Muscle and Its Correlation with Myofascial Trigger Points: Preliminary Results

Poster Board Number: 77
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Co-authors:

Luis Garrido - Fellow Master degree, Surgery, University of São Paulo; Flavia Akamatsu - Professor, Surgery, 116.319.698-38; Flavio Hojaij - PhD, Surgery, University of São Paulo; Mauro Andrade - Professor, Surgery, University of São Paulo; Alfredo Jacomo - Head Professor, Surgery, University of São Paulo

Abstract Body :Background: Temporomandibular dysfunction (TMD) is highly prevalent and presents with preauricular pain and limited opening and closing of the mouth. Myofascial pain may affect masticatory muscles and the lateral pterygoid muscle (LPM) is commonly involved. Whenever LPM harbors myofascial trigger points (MTP), its palpation elicits reflex pain in the maxilar sinus region and temporomandibular joint. Tenderness in the lower border of the muscle is common in patients with TMD and LPM is involved with painful temporomandibular joint. LPM has a superior and an inferior belly and one MTP is described for each of them. Methods: LPM from five cadavers were dissected to characterize their innervation. The entry point of the nerve into the muscle was determined by four areas: I, II, III, and IV. Statistical analysis of anatomical data was obtained by Poisson distribution and logarithm link function followed by Bonferroni multiple comparisons. The comparison of points between the sides was made by t-student test. Data are presented as the mean ± standard deviation, and the level of significance was adjusted to 5% (p < 0.05) for all tests. Results: Nerve branching did not differ among muscle regions (1±1 for all quadrants, except for quadrant IV, with a mean of 2±1 entry points). Conclusion: Identification of the nerve entry points in the LPM can be useful to locate the MTPs and provide anatomical data which may base manipulative and invasive treatment techniques.