Document Detail


Diaphragm muscle shortening modulates kinematics of lower rib cage in dogs.
MedLine Citation:
PMID:  20739605     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We tested the hypothesis that diaphragm muscle shortening modulates volume displacement and kinematics of the lower rib cage in dogs and that posture and mode of ventilation affect such modulation. Radiopaque markers were surgically attached to the lower three ribs of the rib cage and to the midcostal region of the diaphragm in six dogs of ∼8 kg body masses, and the locations of these markers were determined by a biplane fluoroscopy system. Three-dimensional software modeling techniques were used to compute volume displacement and surface area of the midcostal diaphragm and the lower three ribs during quiet spontaneous breathing, mechanical ventilation, and bilateral phrenic nerve stimulation at different lung volumes spanning the vital capacity. Volume displaced by the diaphragm relative to that displaced by the lower ribs is disproportionately greater under mechanical ventilation than during spontaneous breathing in the supine position (P < 0.05). At maximal stimulation, diaphragm volume displacement grows disproportionately larger than rib volume displacement as lung volume increases (P < 0.05). Surface area of both the diaphragm and the lower ribs during maximal stimulation of the diaphragm is reduced compared with that at spontaneous breathing (P < 0.05). In the prone posture, mechanical ventilation results in a smaller change in diaphragm surface area than spontaneous breathing (P < 0.05). Our data demonstrate that during inspiration the lower rib cage moves not only through the pump- and bucket-handle motion, but also rotates around the spine. Taken together, these data support the observation that the kinematics of the lower rib cage and its mechanical interaction with the diaphragm are more complex than previously known.
Authors:
Iris Chu; Cristina Fernandez; Kathleen Allen Rodowicz; Michael A Lopez; Raymond Lu; Rolf D Hubmayr; Aladin M Boriek
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-08-25
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  299     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-07     Completed Date:  2011-01-14     Revised Date:  2011-12-21    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1456-62     Citation Subset:  IM    
Affiliation:
Baylor College of Medicine, Houston, TX 77030, USA.
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Animals
Biomechanics / physiology
Computer Simulation
Diaphragm / physiology*
Dogs
Models, Biological
Muscle Contraction / physiology*
Prone Position / physiology
Respiratory Mechanics / physiology*
Ribs / physiology*
Supine Position / physiology
Grant Support
ID/Acronym/Agency:
HL-072839/HL/NHLBI NIH HHS; HL-63134/HL/NHLBI NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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