82 - Anatomical Substract of the Adductor Pollicis Muscle Myofascial Trigger Points

Poster Board Number: 82
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Co-authors:

Rafael Rocha - graduate student, Surgery, University of São Paulo; Cesar De Alencar - graduate student, Surgery, University of São Paulo; Flávio Hojaij - PhD, Surgery, University of São Paulo; Mauro Andrade - Professor, Surgery, University of São Paulo; Flavia Akamatsu - Professor, Surgery, University of São Paulo

Abstract Body :Background: The overuse of intrinsic muscles of the hand to match the increasing needs related to current communicating devices may be related to myofascial pain syndrome of thenar muscles. Although pathophysiology of MTPs remains unclear, there has been suggested that they coincide with the muscle motor plate at the innervation zone (IZ) have been reported. Clinically, the adductor pollicis (ADD) muscle may be the origin of referred pain and trigger points (TPs). We aimed to describe the nervous branching of the ADD and correlate the findings with previously described TPs.Methods: We dissected the ADD muscles from seven cadavers to observe the exact point where nerve fibers penetrated the muscle belly. As muscle size varies among individuals, we calculated the relative entry point of the nerve into the muscle by defining four different areas in the muscle belly: two superior (I, II) and two inferior (III and IV) for the transverse and oblique heads. 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 Mann-Whitney 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: The number of nerve branches did not differ between sides. Areas I, II, III and IV also did not differ on the number of nerve entry sites, with a mean of 0±1 for oblique head and 1±1 for transverse head for quadrant I and for quadrant II, III and IV the oblique and transverse head showed a mean of 1±1. Conclusion: Identification of the nerve entry points in the ADD muscle can be useful to locate the MTPs so helping manipulative and invasive treatment techniques.