Patterns of intercostal muscle activity in humans

1989 ◽  
Vol 67 (5) ◽  
pp. 2087-2094 ◽  
Author(s):  
W. A. Whitelaw ◽  
T. Feroah
Keyword(s):  
Human Subjects ◽  
Emg Activity ◽  
Deep Breathing ◽  
Flow Volume ◽  
Intercostal Muscle ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Fine Wire ◽  
Midaxillary Line ◽  
Emg Electrodes

Coordination of activity of inspiratory intercostal muscles in conscious human subjects was studied by means of an array of electromyograph (EMG) electrodes. Bipolar fine wire electrodes were placed in the second and fourth parasternal intercostal muscles and in two or three external intercostal muscles in the midaxillary line from the fourth to eighth intercostal spaces. Subjects breathed quietly or rebreathed from a bag containing 8% CO2 in O2 in both supine and upright postures. Respiration was monitored by means of flow, volume, and separate rib cage and abdominal volumes. Onset of EMG activity in each breath was found near the beginning of inspiration in the uppermost intercostal spaces but progressively later in inspiration in lower spaces, indicating that activity spreads downward across the rib cage through inspiration. At higher ventilation stimulated by CO2, activity spread further and faster downward. In voluntary deep breathing, external intercostal muscles tended to be recruited earlier in inspiration than in CO2-stimulated breathing. The change from supine to sitting resulted in small and inconsistent changes. There was no lung volume or rib cage volume threshold for appearance of EMG activity in any of the spaces.

Respiratory changes in thoracic muscle length during bronchoconstriction

1987 ◽  
Vol 63 (1) ◽  
pp. 221-228 ◽  
Author(s):  
E. van Lunteren ◽  
M. A. Haxhiu ◽  
E. C. Deal ◽  
J. S. Arnold ◽  
N. S. Cherniack
Keyword(s):  
Tidal Volume ◽  
Respiratory Muscle ◽  
Muscle Length ◽  
Emg Activity ◽  
Intercostal Muscle ◽  
Mean Velocity ◽  
Intercostal Muscles ◽  
Fine Wire ◽  
Velocity Of Shortening ◽  
The Mean

The purpose of the present study was to assess the effects of bronchoconstriction on respiratory changes in length of the costal diaphragm and the parasternal intercostal muscles. Ten dogs were anesthetized with pentobarbital sodium and tracheostomized. Respiratory changes in muscle length were measured using sonomicrometry, and electromyograms were recorded with bipolar fine-wire electrodes. Administration of histamine aerosols increased pulmonary resistance from 6.4 to 14.5 cmH2O X l–1 X s, caused reductions in inspiratory and expiratory times, and decreased tidal volume. The peak and rate of rise of respiratory muscle electromyogram (EMG) activity increased significantly after histamine administration. Despite these increases, bronchoconstriction reduced diaphragm inspiratory shortening in 9 of 10 dogs and reduced intercostal muscle inspiratory shortening in 7 of 10 animals. The decreases in respiratory muscle tidal shortening were less than the reductions in tidal volume. The mean velocity of diaphragm and intercostal muscle inspiratory shortening increased after histamine administration but to a smaller extent than the rate of rise of EMG activity. This resulted in significant reductions in the ratio of respiratory muscle velocity of shortening to the rate of rise of EMG activity after bronchoconstriction for both the costal diaphragm and the parasternal intercostal muscles. Bronchoconstriction changed muscle end-expiratory length in most animals, but for the group of animals this was statistically significant only for the diaphragm. These results suggest that impairments of diaphragm and parasternal intercostal inspiratory shortening occur after bronchoconstriction; the mechanisms involved include an increased load, a shortening of inspiratory time, and for the diaphragm possibly a reduction in resting length.

Activation of the parasternal intercostals during breathing efforts in human subjects

1982 ◽  
Vol 52 (3) ◽  
pp. 524-529 ◽  
Author(s):  
A. De Troyer ◽  
M. G. Sampson
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Emg Activity ◽  
Tidal Breathing ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Breathing Maneuver ◽  
Inspiratory Activity

We have tested the possibility that the electromyographic (EMG) activity present in the parasternal intercostal muscles during quiet inspiration was reflexive, rather than agonistic, in nature. Using concentric needle electrodes we measured parasternal EMG activity in four normal subjects during various inspiratory maneuvers. We found that 1) phasic inspiratory activity was invariably present in the parasternal intercostals during quiet breathing, 2) the parasternal EMG activity was generally increased during attempts to perform the tidal breathing maneuver with the diaphragm alone, 3) parasternal EMG activity was markedly decreased or suppressed in the presence of rib cage distortion during diaphragmatic isovolume maneuvers, and 4) that EMG activity could not be voluntarily suppressed during breathing unless the inspired volume was trivial. We conclude that the parasternal EMG activity detected during quiet inspiration in the normal subjects depends on a central involuntary mechanism and is not related to activation of intercostal mechanoreceptors.

Coordination between rib cage muscles and diaphragm during quiet breathing in humans

1984 ◽  
Vol 57 (3) ◽  
pp. 899-906 ◽  
Author(s):  
A. De Troyer ◽  
M. Estenne
Keyword(s):  
Tidal Volume ◽  
Marked Reduction ◽  
Emg Activity ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Inspiratory Activity ◽  
Normal Humans ◽  
Volume Range

The pattern of activation of the scalenes and the parasternal intercostal muscles was studied in relation to the pattern of rib cage and abdominal motion during various respiratory maneuvers in the tidal volume range in five normal humans. Electromyograms (EMG) of the scalenes and parasternal intercostals were recorded with bipolar needle electrodes, and changes in abdominal and rib cage displacement were measured using linearized magnetometers. The scalenes and parasternal intercostals were always active during quiet breathing, and their pattern of activation was identical; in both muscles the EMG activity usually started together with the beginning of inspiration, increased in intensity as inspiration proceeded, and persisted into the early part of expiration. In addition, like the parasternal activity the scalene inspiratory activity persisted until the tidal volume was trivial, increased during tidal inspirations performed with the rib cage alone, and was nearly abolished during diaphragmatic isovolume maneuvers. However, attempts to perform tidal inspiration with the diaphragm alone, while causing an increase in parasternal EMG activity, were associated with a marked reduction or a suppression of scalene EMG activity and a reduced substantially distorted rib cage expansion. In particular, the upper rib cage was then moving paradoxically.(ABSTRACT TRUNCATED AT 250 WORDS)

The two mechanisms of intercostal muscle action on the lung

2004 ◽  
Vol 96 (2) ◽  
pp. 483-488 ◽  
Author(s):  
Theodore A. Wilson ◽  
Andre De Troyer
Keyword(s):  
Three Dimensional ◽  
Intercostal Muscle ◽  
Muscle Action ◽  
Opening Pressure ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Airway Opening ◽  
The Difference ◽  
External Forces

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.

An analysis of action of intercostal muscles in human upper rib cage

1986 ◽  
Vol 60 (2) ◽  
pp. 690-701 ◽  
Author(s):  
R. C. Saumarez
Keyword(s):  
Mathematical Model ◽  
Vertebral Column ◽  
Erector Spinae ◽  
Intercostal Muscle ◽  
Paraspinal Muscles ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Physiological Load ◽  
Deep Layers ◽  
Made In

The actions of the intercostal and paraspinal muscles in stabilizing the human upper rib cage have been analyzed using a geometrically realistic mathematical model of the first six ribs, vertebrae, and associated musculature. The model suggests roles of the deep layers of erector spinae in stabilizing the vertebral column so that it can support the loads placed upon it by the ribs under physiological load. If we assume that the tension exerted by an intercostal muscle is proportional to its local thickness, the model predicts that the observed distribution of intercostal thickness is close to that which minimizes the stresses in ribs when the model is subjected to peak physiological load. The observed shape of the ribs are optimal to withstand the calculated pattern of loading along their length. These calculations raise the hypothesis that the arrangement of intercostal musculature and rib geometry result in an optimally light rib cage, which is capable of withstanding the loads placed upon it. The analysis of the mechanics of the entire model indicates that the geometrical simplifications made in Hamberger's model are not valid when applied to the rib cage.

scholarly journals Effect of intercostal muscle contraction on rib motion in humans studied by finite element analysis

2018 ◽  
Vol 125 (4) ◽  
pp. 1165-1170 ◽  
Author(s):  
Guangzhi Zhang ◽  
Xian Chen ◽  
Junji Ohgi ◽  
Fei Jiang ◽  
Seiryo Sugiura ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Muscle Contraction ◽  
Muscle Force ◽  
Special Structure ◽  
Tissue Deformation ◽  
Intercostal Muscle ◽  
Element Analysis ◽  
Rib Cage ◽  
Intercostal Muscles

The effect of intercostal muscle contraction on generating rib motion has been investigated for a long time and is still controversial in physiology. This may be because of the complicated structure of the rib cage, making direct prediction of the relationship between intercostal muscle force and rib movement impossible. Finite element analysis is a useful tool that is good at solving complex structural mechanic problems. In this study, we individually activated the intercostal muscle groups from the dorsal to ventral portions and obtained five different rib motions classified based on rib moving directions. We found that the ribs cannot only rigidly rotate around the spinal joint but also be deformed, particularly around the relatively soft costal cartilages, where the moment of muscle force for the rigid rotation is small. Although the intercostal muscles near the costal cartilages cannot generate a large moment to rotate the ribs, the muscles may still have a potential to deform the costal cartilages and contribute to the expansion and contraction of the rib cage based on the force-length relationship. Our results also indicated that this potential is matched well with the special shape of the costal cartilages, which become progressively oblique in the caudal direction. Compared with the traditional explanation of rib motion, by additionally considering the effect from the tissue deformation, we found that the special structure of the ventral portion of the human rib cage could be of mechanical benefit to the intercostal muscles, generating inspiratory and expiratory rib motions. NEW & NOTEWORTHY Compared with the traditional explanation of rib motion, additionally considering the effect from tissue deformation helps us understand the special structure of the ventral portion of the human rib cage, such that the costal cartilages progressively become oblique and the costochondral junction angles gradually change into nearly right angles from the upper to lower ribs, which could be of mechanical benefit to the intercostal muscles in the ventral portion, generating inspiratory and expiratory rib motions.

Interaction between postural and respiratory control of human intercostal muscles

1995 ◽  
Vol 79 (5) ◽  
pp. 1556-1561 ◽  
Author(s):  
K. P. Rimmer ◽  
G. T. Ford ◽  
W. A. Whitelaw
Keyword(s):  
Chest Wall ◽  
Respiratory Control ◽  
Tonic Activity ◽  
Intercostal Muscles ◽  
Postural Activity ◽  
Fine Wire ◽  
Midaxillary Line ◽  
Lateral Chest ◽  
The Right ◽  
Postural Tone

To study the interaction between postural and respiratory control of intercostal muscles, we used electromyography of intercostal muscles of the lateral chest wall in conscious humans. Bipolar fine-wire electrodes were placed in external and internal intercostal muscles in the midaxillary line of four subjects who sat on a bench and breathed through a pneumotachograph. They were instructed to hold their breath at end expiration, rotate their thorax to the right or left, and then hold the rotation while resuming breathing. Holding a rotation induces steady tonic activity in either internal or external intercostal muscles, depending on the direction of the rotation. The degree of rotation was varied from one run to the next, resulting in varied levels of tonic postural activity. When breathing resumes, internal intercostal muscles have their activity almost completely suppressed with each inspiration independently of whether the tonic postural tone is small or large. External intercostal muscles show inspiratory increases in activity superimposed on the postural tone, which apparently amplifies the effect of respiratory input to their motoneurons.

Parasternal and external intercostal responses to various respiratory maneuvers

1992 ◽  
Vol 73 (3) ◽  
pp. 979-986 ◽  
Author(s):  
A. F. DiMarco ◽  
J. R. Romaniuk ◽  
G. S. Supinski
Keyword(s):  
Muscle Length ◽  
Similar Degree ◽  
Intercostal Muscle ◽  
Abdominal Compression ◽  
Similar Extent ◽  
Rib Cage ◽  
Piezoelectric Crystals ◽  
Intercostal Muscles ◽  
Steel Electrodes

Recent studies suggest that the external intercostal (EI) muscles of the upper rib cage, like the parasternals (PA), play an important ventilatory role, even during eupneic breathing. The purpose of the present study was to further assess the ventilatory role of the EI muscles by determining their response to various static and dynamic respiratory maneuvers and comparing them with the better-studied PA muscles. Applied interventions included 1) passive inflation and deflation, 2) abdominal compression, 3) progressive hypercapnia, and 4) response to bilateral cervical phrenicotomy. Studies were performed in 11 mongrel dogs. Electromyographic (EMG) activities were monitored via bipolar stainless steel electrodes. Muscle length (percentage of resting length) was monitored with piezoelectric crystals. With passive rib cage inflation produced either with a volume syringe or abdominal compression, each muscle shortened; with passive deflation, each muscle lengthened. During eupneic breathing, each muscle was electrically active and shortened to a similar degree. In response to progressive hypercapnia, peak EMG of each intercostal muscle increased linearly and to a similar extent. Inspiratory shortening also increased progressively with increasing PCO2, but in a curvilinear fashion with no significant differences in response among intercostal muscles. In response to phrenicotomy, the EMG and degree of inspiratory shortening of each intercostal muscle increased significantly. Again, the response among intercostal muscles was not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory function of intercostal muscles in supine dog: an electromyographic study

1986 ◽  
Vol 60 (5) ◽  
pp. 1692-1699 ◽  
Author(s):  
A. De Troyer ◽  
V. Ninane
Keyword(s):  
Respiratory Function ◽  
Traditional View ◽  
Lower Portion ◽  
Intercostal Muscle ◽  
Muscle Action ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Anesthetized Dogs ◽  
The Difference

It is traditionally considered that the difference in orientation of the muscle fibers makes the external intercostals elevate the ribs and the internal interosseous intercostals lower the ribs during breathing. This traditional view, however, has recently been challenged by the observation that the external and internal interosseous intercostals, when contracting alone in a single interspace, have a similar effect on the ribs into which they insert. This view has also been challenged by the observation that the external and internal intercostals in a given interspace often change their length in the same direction during breathing. In an attempt to clarify the respiratory function of these muscles, we studied eight supine lightly anesthetized dogs during quiet breathing and during static inspiratory efforts. In each animal electromyographic (EMG) recordings from the external and internal interosseous intercostals were obtained in all interspaces from the second to the eighth, and selective denervations were systematically performed to ensure with complete certainty the origin of the recorded EMG activities. The external intercostals were only activated in phase with inspiration, whereas the internal interosseous intercostals were only activated in phase with expiration. These phasic EMG activities, however, were generally small in magnitude, and the muscles were often silent. Indeed, activation of the externals was always confined to the upper portion of the rib cage, whereas activation of the internals was limited to the lower portion of the rib cage. Internal intercostal activation always occurred sequentially along a caudocephalic gradient. These observations are thus compatible with the traditional view of intercostal muscle action.(ABSTRACT TRUNCATED AT 250 WORDS)

Action of intercostal muscles on the lung in dogs

1991 ◽  
Vol 70 (6) ◽  
pp. 2388-2394 ◽  
Author(s):  
V. Ninane ◽  
M. Gorini ◽  
M. Estenne
Keyword(s):  
Lung Volume ◽  
Internal Layer ◽  
Airflow Rate ◽  
Intercostal Muscle ◽  
Similar Action ◽  
Rib Cage ◽  
Intercostal Muscles ◽  
Maximal Stimulation ◽  
Residual Capacity ◽  
Stimulation Of

The action on the lung of interosseous intercostal muscles located in the third and the seventh interspaces was studied in 15 anesthetized-curarized supine dogs. Changes in pleural pressure, airflow rate, and lung volume produced by maximal stimulation of both intercostal muscle layers were measured at and above functional residual capacity (FRC). In five animals measurements were also obtained during isolated stimulation of the internal layer. At FRC, intercostal stimulation in the upper interspaces had invariably an inspiratory effect on the lung but no effect was detectable in the lower interspaces. Qualitatively similar results were obtained during isolated stimulation of the internal layer. Increasing lung volume reduced the inspiratory action of the upper intercostals and conferred an expiratory action to the lower intercostals. These results indicate the following: 1) when contracting in a single interspace, the external and internal intercostals have a qualitatively similar action on the lung; and 2) this action, however, depends critically on their location along the cephalocaudal axis of the rib cage: in the upper portion of the rib cage, both muscle layers have an inspiratory effect at and above FRC; in the lower portion of the rib cage, they have no respiratory action at FRC and act in the expiratory direction at higher lung volumes.

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