Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 80: 852-856, 1996;
8750-7587/96 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Muza, S. R.
Right arrow Articles by Kelsen, S. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Muza, S. R.
Right arrow Articles by Kelsen, S. G.

Journal of Applied Physiology, Vol 80, Issue 3 852-856, Copyright © 1996 by American Physiological Society

ARTICLES

Effect of lung volume on the respiratory action of the canine sternomastoid

S. R. Muza, G. J. Criner and S. G. Kelsen
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.

We tested the hypothesis that because the resting length of the canine sternomastoid (SM) muscles is relatively insensitive to lung volume change, the SM may maintain its inspiratory force generation regardless of lung volume. The relationships between SM pre- and postcontraction in situ fiber lengths and SM-produced inspiratory pressure generation [i.e., esophageal (Pes)] and rib cage displacements were examined in adult supine anesthetized dogs at residual volume (RV), functional residual capacity, and total lung capacity. SM muscle contraction was produced by isolated bilateral supramaximal electrical stimulation during hyperventilation-induced apnea. In all animals, SM contraction produced negative change in Pes (i.e., an inspiratory action). Passively increasing lung volume from RV to total lung capacity decreased (P < or = 0.01) the SM-produced Pes by -66 +/- 4% but had a relatively small effect on SM in situ pre- and postcontraction fiber length (< 3%). Whereas SM contraction at RV produced a cranial displacement of the sternum and increased the upper rib cage cross-sectional area, passively elevating lung volume diminished the SM-produced expansion of the upper rib cage. Hyperinflation did not increase the impedance of the sternum to cranial displacement during SM contraction, suggesting that hyperinflation caused a dissociation between the mechanical action of the sternum and the upper rib cage. These results suggest that mechanical dissociation of the ribs and sternum may diminish the contribution of the SM to inspiratory volume generation when breathing is done from elevated end-expiratory lung volumes.


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
A. Legrand, V. Ninane, and A. De Troyer
Mechanical advantage of sternomastoid and scalene muscles in dogs
J Appl Physiol, May 1, 1997; 82(5): 1517 - 1522.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online