Anatomical Basis of the Myofascial Trigger Points of the Trapezius Muscle

Abstract

This study aimed to bring the trapezius muscle, knowledge of the locations where the accessory nerve branches enter the muscle belly to reach the motor endplates and find myofascial trigger points (MTPs). Although anatomoclinical correlations represent a major feature of MTP, no previous reports describing the distribution of the accessory nerve branches and their anatomical relationship with MTP are found in the literature. Both trapezius muscles from twelve adult cadavers were carefully dissected by the authors (anatomy professors and medical graduate students) to observe the exact point where the branches of the spinal accessory nerve entered the muscle belly. Dissection was performed through stratigraphic layers to preserve the motor innervation of the trapezius muscle, which is located deep in the muscle. Eight points were identified: In all cases, these locations corresponded to clinically described MTPs. The eight points where common in these twelve cadavers. This type of clinical correlation between spinal accessory nerve branching and MPT is useful to achieve a better understanding of the anatomical correlation of MTP and the physiopathology of these disorders and may provide a scientific basis for their treatment, providing useful additional information to therapists to achieve better diagnoses and improve therapeutic approaches.