Journal of Applied Physiology, Vol 62, Issue 3 919-925, Copyright © 1987 by American Physiological Society

ARTICLES

Triangularis sterni muscle use in supine humans

A. De Troyer, V. Ninane, J. J. Gilmartin, C. Lemerre and M. Estenne

The electrical activity of the triangularis sterni (transversus thoracis) muscle was studied in supine humans during resting breathing and a variety of respiratory and nonrespiratory maneuvers known to bring the abdominal muscles into action. Twelve normal subjects, of whom seven were uninformed and untrained, were investigated. The electromyogram of the triangularis sterni was recorded using a concentric needle electrode, and it was compared with the electromyograms of the abdominal (external oblique and rectus abdominis) muscles. The triangularis sterni was usually silent during resting breathing. In contrast, the muscle was invariably activated during expiration from functional residual capacity, expulsive maneuvers, "belly-in" isovolume maneuvers, static head flexion and trunk rotation, and spontaneous events such as speech, coughing, and laughter. When three trained subjects expired voluntarily with considerable recruitment of the triangularis sterni and no abdominal muscle activity, rib cage volume decreased and abdominal volume increased. These results indicate that unlike in the dog, spontaneous quiet expiration in supine humans is essentially a passive process; the human triangularis sterni, however, is a primary muscle of expiration; and its neural activation is largely coupled with that of the abdominals. The triangularis sterni probably contributes to the deflation of the rib cage during active expiration.

This article has been cited by other articles:

				B. J. Taylor, S. C. How, and L. M. Romer Exercise-induced abdominal muscle fatigue in healthy humans J Appl Physiol, May 1, 2006; 100(5): 1554 - 1562. [Abstract] [Full Text] [PDF]

				A. De Troyer, P. A. Kirkwood, and T. A. Wilson Respiratory Action of the Intercostal Muscles Physiol Rev, April 1, 2005; 85(2): 717 - 756. [Abstract] [Full Text] [PDF]

				S. G. ZAKYNTHINOS, T. VASSILAKOPOULOS, E. ZAKYNTHINOS, A. MAVROMMATIS, and C. ROUSSOS Contribution of Expiratory Muscle Pressure to Dynamic Intrinsic Positive End-Expiratory Pressure . Validation Using the Campbell Diagram Am. J. Respir. Crit. Care Med., November 1, 2000; 162(5): 1633 - 1640. [Abstract] [Full Text]

				A. De Troyer, A. Legrand, P.-A. Gevenois, and T. A Wilson Mechanical advantage of the human parasternal intercostal and triangularis sterni muscles J. Physiol., December 15, 1998; 513(3): 915 - 925. [Abstract] [Full Text] [PDF]

				M. Beaumont, D. Lejeune, H. Marotte, A. Harf, and F. Lofaso Effects of chest wall counterpressures on lung mechanics under high levels of CPAP in humans J Appl Physiol, August 1, 1997; 83(2): 591 - 598. [Abstract] [Full Text] [PDF]

				T. F. Schuessler, S. B. Gottfried, and J. H. T. Bates A model of the spontaneously breathing patient: applications to intrinsic PEEP and work of breathing J Appl Physiol, May 1, 1997; 82(5): 1694 - 1703. [Abstract] [Full Text] [PDF]

				M. Estenne and A. De Troyer Cough in Tetraplegic Subjects: An Active Process Ann Intern Med, January 1, 1990; 112(1): 22 - 28. [Abstract] [PDF]