|
|
||||||||
Journal of Applied Physiology, Vol 69, Issue 6 2222-2226, Copyright © 1990 by American Physiological Society
ARTICLES |
A. F. DiMarco, J. R. Romaniuk and G. S. Supinski
Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44109.
The interosseous external intercostal (EI) muscles of the upper rib cage are electrically active during inspiration, but the mechanical consequence of their activation is unclear. In 16 anesthetized dogs, we simultaneously measured EI (3rd and 4th interspaces) and parasternal intercostal (PA) (3rd interspace) electromyogram and length. Muscle length was measured by sonomicrometry and expressed as a percentage of resting length (%LR). During resting breathing, each muscle was electrically active and shortened to a similar extent. Sequential EI muscle denervation (3rd and 4th interspaces) followed by PA denervation (3rd interspace) demonstrated significant reductions in the degree of inspiratory shortening for each muscle. Mean EI muscle shortening of the third and fourth interspaces decreased from -3.4 +/- 0.5 and -3.0 +/- 0.4% LR (SE) under control conditions to -0.2 +/- 0.2 and -0.8 +/- 0.3% LR, respectively, after selective denervation of each of these muscles (P less than 0.001 for each). After selective denervation of the PA muscle, its shortening decreased from -3.5 +/- 0.3 to +0.6% LR (SE) (P less than 0.001). PA muscle denervation also caused the EI muscle in the third interspace to change from inspiratory shortening of -0.2% to inspiratory lengthening of +0.2% +/- 0.2 (P less than 0.05). We conclude that during eupneic breathing 1) the EI muscles of the upper rib cage, like the PA muscles, are inspiratory agonists and actively contribute to rib cage expansion and 2) PA muscle contraction contributes to EI muscle shortening.
This article has been cited by other articles:
![]() |
C. Casadevall, C. Coronell, A. L. Ramirez-Sarmiento, J. Martinez-Llorens, E. Barreiro, M. Orozco-Levi, J. Gea, and on behalf of the ENIGMA in COPD group Upregulation of pro-inflammatory cytokines in the intercostal muscles of COPD patients Eur. Respir. J., October 1, 2007; 30(4): 701 - 707. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Wu and G. B. Drummond Respiratory muscle activity and respiratory obstruction after abdominal surgery Br. J. Anaesth., April 1, 2006; 96(4): 510 - 515. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Cappello and A. De Troyer On the respiratory function of the ribs J Appl Physiol, April 1, 2002; 92(4): 1642 - 1646. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. A. Easton, H. G. Hawes, B. Rothwell, and A. de Troyer Postinspiratory activity of the parasternal and external intercostal muscles in awake canines J Appl Physiol, September 1, 1999; 87(3): 1097 - 1101. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |