An Assessment Framework of the Shoulder Girdle in Participants with Temporomandibular Disorders

Abstract

The general population is prone to developing temporomandibular disorders (TMD) due to the complexity of the temporomandibular joint (TMJ), the high number of times the joint is used daily, and the increasing prevalence of parafunctional habits which overload the joint and muscles. This thesis aimed to develop an assessment framework of the shoulder girdle in participants with TMD, with four original studies emanating from this project. The first was a scoping review that mapped out the anatomical, neuromuscular and neurophysiological connections between the TMJ and shoulder girdle and included a total of 41 articles. The second study was a questionnaire that included 186 people with TMD. The result showed that 56% of participants had shoulder pain and 45% had received previous shoulder treatment. A significant positive correlation was found between the level of TMD and pain and disability of the shoulder, with the same findings in the third study. The third study tested muscle activity of the biceps, medial deltoid, infraspinatus, inferior trapezius and serratus anterior at rest, during active and jaw-resisted movements, and weighted shoulder flexion and abduction. The findings were that participants with TMD, had a lower muscle activity at rest, during jaw and shoulder movements compared to those without TMD. The muscles that showed significant differences between the two groups were the right infraspinatus during shoulder flexion (p = 0.004) and abduction (p = 0.049), and the right biceps (p = 0.049) and left infraspinatus (p = 0.022) during shoulder abduction. The results from these and other studies were taken and a framework was created. Through the use of the Delphi method (Study 4), it was distributed to a panel of international physiotherapy experts to gain consensus on the contents. The final framework included four subjective questions and two objective measures. The overall findings showed that there are associations between pain, disability, and dysfunction of the TMJ and shoulder girdle in participants with TMD. Furthermore, there are differences in the activity of the shoulder girdle muscles during jaw and shoulder movements in those with and without TMD, with variances among the different muscles