Activation of masseter muscles with inspiratory resistance loading

Abstract

Closure of the jaw exerts traction on muscles that insert on the hyoid bone and that may stabilize or expand the pharyngeal airway. We postulated that the masseter muscles, which close the jaw, would be activated when the patency of the pharyngeal airway is threatened. We therefore measured electromyographic activation of the masseters during inspiratory resistance loading and compared it with activation of chin muscles and alae nasi in 10 normal subjects. We observed no masseter activation during quiet unloaded breathing, but as pharyngeal pressure became lower there was a significant increase in masseter activation in all subjects. The change in masseter activation relative to pharyngeal pressure was similar to that of chin muscles and alae nasi. Activation of the masseter preceded the fall in pharyngeal pressure as also occurred in the chin muscles and alae nasi. We conclude that the masseters are activated by inspiratory resistance loading and have respiratory activity similar to pharyngeal airway muscles.

A polysomnographic study on masticatory and tongue muscle activity during obstructive and central sleep apnea

“…Remmers et al (1978) reported that the genioglossal electromyogram in patients with obstructive sleep apnea syndrome consistently revealed periodicity; low level activity at the onset of obstruction and prominent discharge at the instant of pharyngeal opening. Hollowell & Suratt (1989) found that masseter muscle activation occurred in patients with obstructive sleep apnea syndrome and in a pattern similar to that of submental muscles. Also in the present study the masseter muscle, the genioglossal muscle and the inferior head of the lateral pterygoid muscle showed lower amplitudes during obstructive apnea and higher amplitudes after the apnea (Fig.…”

“…1). The coactivation of agonist (the genioglossal muscle and the lateral pterygoid muscle) and antagonist (the masseter muscle) after the apnea was postulated to stabilize the mandible to prevent the upper airways from collapsing (Hollowell & Suratt, 1989). Hollowell & Suratt (1991) reported that the jaws of patients with obstructive sleep apnea were open more widely than those of normal subjects at the end of expiration and opened further at the end of inspiration, particularly at the termination of apneas when the masseter and submental muscles contracted.…”

Neural mechanisms underlying respiratory rhythm generation in the lamprey

“…Interestingly, trigeminal motoneurons display rhythmic respiratory activity in newborn rodents (e.g. Jacquin et al, 1999;Koizumi et al, 1999Koizumi et al, , 2002 and even in humans especially under particular conditions (Sauerland et al, 1981;StJohn and Bledsoe, 1985;Hollowell and Suratt, 1989;Hollowell et al, 1991). These findings may possibly account for the persistence of vestiges of the original trigeminal oscillator and for the high homology between the pTRG and the preBötC.…”

Mandibular Movements As Accurate Reporters of Respiratory Effort during Sleep: Validation against Diaphragmatic Electromyography

“…However, REM sleep stage has a fixed effect of MM amplitude reduction reflecting the reduction in neural respiratory drive to the respiratory musculature associated with this sleep stage. Beyond central respiratory drive originating in the brainstem impacting motoneurons innervating the diaphragm, there are active nuclei involved in the recruitment and relaxation of muscles controlling MM (33). These nuclei are also independently subjected to REM sleep atonia (34).…”