Videofluoroscopic assessment of muscle fiber shortening in the in situ canine diaphragm

H. Knight, W. M. Petroll, J. M. Adams, H. A. Shaffer, D. F. Rochester

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We tested the hypothesis that dynamic shortening of the costal diaphragm can be accurately estimated from measurements of the radiographic width of the zone of apposition (W(Zapp)) by studying seven supine anesthetized dogs. Both muscle fiber length, represented by the distance between implanted radiopaque markers, and W(Zapp) were measured from digitized recordings of fluoroscopic images utilizing interactive computer software. The W(Zapp) was highly correlated with the length of costal fibers during active respiration in all animals (mean R2 = 0.94). The accuracy in the prediction of fiber length and shortening during breathing is enhanced by inclusion of additional variables describing the displacement of the abdominal wall and the resting geometric orientation of the fibers. We conclude that dynamic fluoroscopic measurement of W(Zapp) is a valuable technique for estimating dynamic diaphragm fiber length and shortening. Depending on the experimental circumstances, W(Zapp) may be a more easily acquired indicator of diaphragm shortening than other variables that have been previously utilized. As such, it may provide a suitable approach to assess active shortening of the diaphragm in humans.

Original languageEnglish (US)
Pages (from-to)2200-2207
Number of pages8
JournalJournal of applied physiology
Issue number5
StatePublished - 1990


  • Respitrace
  • costal diaphragm
  • diaphragm length
  • fluoroscopy
  • mechanics of breathing
  • zone of apposition

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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