|
|
||||||||
Journal of Applied Physiology, Vol 75, Issue 3 1150-1154, Copyright © 1993 by American Physiological Society
ARTICLES |
S. G. Kelsen, S. Bao, A. J. Thomas, I. A. Mardini and G. J. Criner
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
The parasternal intercostals are primary inspiratory muscles like the costal and crural diaphragm. However, the structure of the rib cage and its impedance to inspiration and expiration varies regionally. We questioned whether topographic differences in rib cage structure and impedance were associated with regional differences in parasternal intercostal muscle structure. Therefore, we examined the size and percentage of histochemically stained fibers in the parasternal intercostal muscles in the first, second, third, fourth, and sixth interspaces in the hamster. We observed a rostrocaudal gradient in the percentage and size of slow oxidative (SO), fast oxidative-glycolytic, and fast glycolytic (FG) fibers in the parasternal intercostal muscles. In particular, the percentage of SO decreased while the percentage of FG increased in a rostrocaudal direction in the first through sixth interspaces. In addition, the size of SO and FG fibers increased from the first to sixth interspace. Furthermore, changes in the size and percent of the three fiber types produced, in a rostrocaudal direction, significant reductions in the relative mass of the parasternal intercostal muscle made up of SO fibers and increases in the mass of fast fibers. We speculate that topographical differences in the size and percentage of fast and slow twitch fibers in the parasternal intercostal are likely to alter force-generating capacity of the parasternal muscles in a rostrocaudal direction and likely reflect regional differences in muscle load and/or activity.
This article has been cited by other articles:
![]() |
S. Levine, T. Nguyen, M. Friscia, J. Zhu, W. Szeto, J. C. Kucharczuk, B. A. Tikunov, N. A. Rubinstein, L. R. Kaiser, and J. B. Shrager Parasternal intercostal muscle remodeling in severe chronic obstructive pulmonary disease J Appl Physiol, November 1, 2006; 101(5): 1297 - 1302. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Laws and A. Hoey Progression of kyphosis in mdx mice J Appl Physiol, November 1, 2004; 97(5): 1970 - 1977. [Abstract] [Full Text] [PDF] |
||||
![]() |
W.-Z. Zhan, C. B. Mantilla, P. Zhan, A. Bitton, Y. S. Prakash, A. de Troyer, and G. C. Sieck Regional differences in serotonergic input to canine parasternal intercostal motoneurons J Appl Physiol, May 1, 2000; 88(5): 1581 - 1589. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |