(Dutton, 2012) The medial pterygoid originates on the medial surface of the lateral pterygoid plate and tuberosity of the maxilla and inserts on the medial surface of the mandible close to the angle (Dutton, 2012). These two muscles meet at the angle of the mandible to form a strong common tendinous insertion known as the pterygomasseteric sling (Thomas & Yaremchuk, 2009). During TM joint replacement, the extraoral approach requires exposure of the inferior border of the mandible requiring disruption of the pterygomasseteric sling, disruption of the sling can also occur through an intraoral approach as well (Thomas & Yaremchuk, 2009). The reason behind this is the masseter muscle must be reflected to allow for the prosthesis to be placed properly and precisely. When reattaching the masseter muscle, proper caution must be practiced during operation. To successfully complete this, the platysma must be divided and the surgeon must place caution to not disect the marginal branch of the facial nerve or …show more content…
A According to Rausita et al, organic changes in a painful joint have been shown to impair the function of the nearby muscles. (Raustia, Oikarinen, & Pernu, 1997) A study created by Rausita et al. found that the functional activity of the masseter in specific has been found to decrease due to this. Along with decreased functional activity, changes in muscular activity take place such as muscle atrophy and fatty replacement. (Raustia et al., 1997). The study consisted of 15 patients with TM disorder, 5 being men and 10 being women. The study compared electrical activity of the masseter and temporal muscles before surgery as well as 3 months, 6 months and 12 months post surgery. The functional tasks that were performed during the study was maximal bite as well as chewing. The study showed that there was a decrease in both temporal and masseter muscle electrical activity on the operated and non operative sides 3 months after surgery. (Raustia et al., 1997). These values returned to normal after 6 months post surgery. During the 1 year follow up, it appeared that the muscles on the surgical side continued to improve unlike the muscles on the surgical side. During chewing activities, there was a noted decrease in activity of the masseter and temporal muscles on the non operated side but not on the operated side at 3 months.