Relation between neck accessory inspiratory muscle electromyographic activity and lung volume

Years ago it was reported that, as lung volume increased, there was a corresponding increase in scalene EMG activity (Raper et al. J Appl Physiol 21: 497-502, 1966). Otherwise, the relationship between changing lung volume and the EMG of the respiratory muscles has not been defined. We therefore ins...

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Bibliographic Details
Published inNihon Kokyūki Gakkai zasshi = the journal of the Japanese Respiratory Society Vol. 39; no. 4; p. 244
Main Authors Masubuchi, Y, Abe, T, Yokoba, M, Yamada, T, Katagiri, M, Tomita, T
Format Journal Article
LanguageJapanese
Published Japan 01.04.2001
Subjects
Adult
Diaphragm - physiology
Electromyography
Humans
Intercostal Muscles - physiology
Lung Volume Measurements
Male
Neck Muscles - physiology
Respiratory Muscles - physiology
Total Lung Capacity - physiology
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Summary:Years ago it was reported that, as lung volume increased, there was a corresponding increase in scalene EMG activity (Raper et al. J Appl Physiol 21: 497-502, 1966). Otherwise, the relationship between changing lung volume and the EMG of the respiratory muscles has not been defined. We therefore inserted fine wire electrodes into the scalene (SCLN), sternocleidomastoid (STERNO), and trapezius (TRAPEZ) muscles in 6 healthy subjects under direct vision using high-resolution ultrasound. Maximum EMG activity (EMGmax) was obtained for each muscle by a variety of respiratory and postural maneuvers. Then, in the standing posture, air flow, raw and moving average EMG signals were sampled and input to a computer during quasi-static inspiration from functional residual capacity (FRC) to total lung capacity (TLC). We found that the relationship between EMG and lung volume for SCLN, but not for STERNO or TRAPEZ, was expressed by exponential curves. The onset of SCLN, STERNO and TRAPEZ EMG occurred at 13.3 +/- 7.4 (mean +/- SE), 67.8 +/- 14.6, and 89.2 +/- 3.9% of inspiratory capacity. The EMG of SCLN, STERNO, TRAPEZ, reached 85.7 +/- 2.6, 60.7 +/- 8.6, and 11.8 +/- 5.2% of EMGmax, respectively, at TLC. We conclude that: 1) SCLN is the most, and TRAPEZ the least, active neck accessory inspiratory muscle, while STERNO is intermediate, and 2) there is a lung volume dependency of the neck accessory muscle EMG activity.
ISSN:1343-3490