HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Wilson, T. A. Articles by De Troyer, A. Search for Related Content PubMed PubMed Citation Articles by Wilson, T. A. Articles by De Troyer, A.

The two mechanisms of intercostal muscle action on the lung

¹Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis, Minnesota 55455; and ²Laboratory of Cardiorespiratory Physiology, Brussels School of Medicine, Erasme University Hospital, 1070 Brussels, Belgium

Submitted 27 May 2003 ; accepted in final form 15 September 2003

The mechanisms of respiratory action of the intercostal muscles were studied by measuring the effect of external forces (F) applied to the ribs and by modeling the effect of F exerted by the intercostal muscles. In five dogs, with the airway occluded, cranial F were applied to individual rib pairs, from the 2nd to the 11th rib pair, and the change in airway opening pressure (Pao) was measured. The ratio Pao/F increases with increasing rib number in the upper ribs (2nd to 5th) and decreases in the lower ribs (5th to 11th). These data were incorporated into a model for the geometry of the ribs and intercostal muscles, and Pao/F was calculated from the model. For interspaces 2-8, the calculated values agree reasonably well with previously measured values. From the modeling, two mechanisms of intercostal muscle action are identified. One is the well-known Hamberger mechanism, modified to account for the three-dimensional geometry of the rib cage. This mechanism depends on the slant of an intercostal muscle relative to the ribs and on the resulting difference between the moments applied to the upper and lower ribs that bound each interspace. The second is a new mechanism that depends on the difference between the values of Pao/F for the upper and lower ribs.

rib-lung coupling; mechanical advantage; Hamberger; dog

This article has been cited by other articles:

				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]