Cervical Myofascial Pain Is Associated with an Imbalance of Masticatory Muscle Activity

Abstract

This study aimed to assess the relationship between the occurrence of cervical myofascial pain with active myofascial trigger points (MTrPs) within the upper trapezius muscle and the electromyographic asymmetry index (AsI) of masticatory muscles: temporalis anterior (TA), superficial part of the masseter muscle (MM), and anterior belly of the digastric muscle (DA). The study group comprised 100 subjects (80 women and 20 men) aged 18 to 30 years (mean 23 ± 2.6 years) reporting pain in the neck muscles, diagnosed with myofascial pain with active MTrPs only within the upper trapezius muscle. The control group comprised 60 healthy, pain-free subjects (42 women and 18 men) aged 20 to 30 years (mean 22.8 ± 2.6 years) without MTrPs in the upper trapezius muscle. The palpation measurement, based on the diagnostic criteria of Travell and Simons, was used to diagnose active MTrPs. The masticatory muscle activity was recorded using an 8-channel device for surface electromyography—BioEMG IIITM. Significant differences in electromyographic patterns between the group with MTrPs in the right side of upper trapezius muscle and the control group were observed within resting activity for the AsI TA (MTrPs: 8.64 vs. controls: −3.22; p = 0.001) and AsI MM (MTrPs: 7.05 vs. controls: −2.09; p = 0.018). Controls presented different electromyographic patterns during maximum voluntary clenching with cotton rolls between teeth within masseter muscle compared to the MTrPs group (MTrPs: 9.27 vs. controls: −0.43 vs. p = 0.041). Participants with MTrPs in the left side of upper trapezius muscle presented predomination of left-sided electromyographic patterns at rest within temporalis anterior in comparison to controls (MTrPs: −19.22 vs. controls: -3.22; p = 0.001). MTrPs within the trapezius muscle may be related to asymmetry within the masticatory muscle activity, suggesting that the presence of myofascial pain within the cervical muscles plays a role in the imbalance of the stomatognathic system. A unilateral active MTrPs within the trapezius muscle may increase the sEMG activity on the same side of the temporalis anterior and masseter muscles.

Influence of Soft Stabilization Splint on Electromyographic Patterns in Masticatory and Neck Muscles in Healthy Women

“…The repeatability of the sEMG procedure was verified with duplicate sEMG examinations on 10 participants, as previously reported [ 33 ]. An analysis of power was conducted using the G*Power 3.1.9.7 program (Heinrich Heine University Düsseldorf, Germany) [ 34 ].…”

Impact of Movement Control Training Using a Laser Device on the Neck Pain and Movement of Patients with Cervicogenic Headache: A Pilot Study

“…Several studies have investigated the relationship between cervical pain and TMD, and the presence of trigger points in the cervical muscles is very common [68][69][70]. Furthermore, MTrps in the neck and head muscles can cause headaches [71] and the presence of MTrps in the trapezius muscle can lead to TMJ imbalance and overloading of the masticatory muscles [72,73]. The masticatory muscles are innervated by the trigeminal nerve and converge with the trigeminocervical nucleus, the nociceptive nucleus of the upper cervical spine, which can be a cause of cervical headaches [74].…”

Altered muscle recruitment patterns during isometric shoulder abduction in individuals with chronic upper trapezius pain: a cross sectional study

“…Many previous studies have compared the muscle activities between individuals with and without UT pain [7,[31][32][33]. However, this is the first reported study to compare muscle activities, the EMG activity ratio, and the relative contribution of primary and synergic muscles during isometric shoulder abduction under different loads (low [25%], middle [50%], and high [75%]) between groups with and without UT pain.…”