Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INTERCOSTAL MUSCLES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,243 records · Page 69Linked to original sources
PubMed1979

A mathematical and graphical analysis of inspiratory muscle action.

In this paper a mathematical and graphical analysis is presented for the action of the diaphragm and the intercostal/accessory muscles of inspiration, in terms of the pressure developed, the volumes displaced and the work performed by each set of muscles. An analogous model is described which behaves according to the analysis. The critical variable by which the action of the diaphragm and intercostal/accessory muscles can be measured is the change in abdominal pressure Pab. When delta Pab = 0 it is assumed that the diaphragm has contracted isometrically and is acting as a fixator preventing an expiratory displacement of the abdomen. When delta Pab greater than 0 the diaphragm shortens and acts as an agonist. When delta Pab less than 0 the diaphragm lengthens as it contracts, performs negative work and the abdomen is displaced in an expiratory direction. For a given change in lung volume, as delta Pab diminishes, there is progressive recruitment of intercostal/accessory muscles and a progressive increase in the work of breathing over and above that required to produce the same change in lung volume by contraction of the diaphragm alone. For values of delta Pab greater than 0 the sum of diaphragm and intercostal/accessory muscle work is less than the total work, because of an increase in the elastic energy stored in the rib cage. For Pab less than 0 there is a decrease in the elastic energy stored in the rib cage leading to a marked increase in work performed and pressures developed by the intercostal/accessory muscles.

Abdomen↗
PubMed1978

Thoracico-abdominal respiratory correlations in infants: constancy and variability in different sleep states.

28 polygraphic recordings were made in normal infants: 20 in full-term newborns and 8 in 2- to 10-wk-old babies. Data were analysed by 20-sec epochs. Relationships between thoracic (3rd-4th rib level) and abdominal respiratory movements were studied according to their maximum out-of-phase occurring (180 degrees maximum) in every 20-sec period. The thoracico-abdominal phase relationships according to sleep states do not change during the first trimester of life. In quiet sleep, while in-pase thoracico-abdominal respiration was the most frequent pattern, the out-of-phase one was also a possible pattern. In active sleep, out-of-phase respiration is characteristic, in-phase relation being a rare exception. In transitional sleep, respiratory relationships could be those appropriate for the preceding or the following sleep state. Nasal air flow always occurred in the phase with abdominal movements. Total flatteninf of thoracicorespiratory movements only were found in all sleep states; these thoracic flattenings must be differentiated from apnea. Transient fluctuations in the degree of phase relations are possible. There exists both interand intraindividual variability in normal infants. Variability of fusimotor system tonus is probably the neurological mechanism underling these phenomena.

Abdominal Muscles↗
PubMed1982

Nonhomogeneous alveolar pressure swings: effect of different respiratory muscles.

We tested the hypothesis in dogs that during isovolumic inspiratory efforts the degree of nonhomogeneity of alveolar pressure changes is influenced by regional differences in respiratory muscle activity. Pressure distal to an occluded right lower lobe bronchus (PRLL) was compared with pressure in the occluded airway opening (PaO) during spontaneous inspiratory efforts (S), during right (RP), left (LP), and bilateral (BP) phrenic nerve stimulation, and during spontaneous inspiratory efforts after cutting both phrenic nerves (SCP), Upper and lower rib cage and abdominal dimensional changes were monitored by magnetometers. PRLL was greater than Pao during S and the difference was greater during BP and greater during RP, whereas with LP and SCP Pao exceeded PRLL. Compared with S, during RP, LP, and BP there was greater upper rib cage inward motion relative to abdominal outward motion. SCP resulted in opposite upper rib cage-abdomen relative motions. Thus activities of various muscle groups produced different regional pressures and deformations of rib cage and abdomen. These results may relate to potential errors in plethysmographic determination of thoracic gas volume in the presence of airway closure.

Abdominal Muscles↗
PubMed1984

[Fatigue of the respiratory muscles].

When respiratory muscle demands for energy exceed supplies, the energy stored within the muscles is depleted and the force of contraction diminishes. This state is called inspiratory muscle fatigue. When it occurs alveolar ventilation decreases, arterial carbon dioxide tension (Pa CO2), increases and hypercapnic respiratory failure ensues. It has also been suggested that such a dysfunction of the respiratory muscles contributes to the pathogenesis of dyspnoea. The purpose of this article is to review: those factors that predispose to respiratory muscle fatigue and determine energy demand and supply, and the principal means of investigation available, including the study of pressures created by muscular contraction, and electromyography.

Abdominal Muscles↗
PubMed1998

Changing central nervous system control following intercostal nerve transfer.

OBJECT: The goal of this study was to find which central nervous system (CNS) pathways are involved in volitional control over reinnervated biceps or pectoral muscles. METHODS: Intercostal nerves (ICNs) were coapted to the musculocutaneous nerve (MCN) or the medial pectoral nerve (MPN) in 23 patients with root avulsions of the brachial plexus to restore biceps or pectoral muscle function. The facilitatory effects of respiration and voluntary contraction on cortical motor-evoked potentials of biceps or pectoral muscles were used to study CNS control over the reinnervated muscles. The time course of the facilitatory effect of respiration and voluntary contraction differed significantly. In the end stage of nerve regeneration, the facilitatory effect of voluntary contraction was significantly larger than that of respiration, indicating that the CNS control network over the muscle comes to resemble that of the recipient nerve (MCN or MPN) rather than that of the donor nerve (ICN). CONCLUSIONS: The strengthening of previously subthreshold synaptic connections in a CNS network connecting ICN to MCN or MPN neurons may underlie changing excitability.

Adult↗
PubMed1992

Observation of the anterior supracostal muscles.

A pair of anomalous supernumerary muscles has been found in a single cadaver which fit the classic description of the Musculus supracostalis anterior. The muscles took origin from the first rib deep to the two pectoral muscles and between the origins of the pectoralis minor and serratus anterior muscles. They were directed inferiorly to insert on the upper margin of the fourth rib. The nerve supply of one muscle of the pair was determined to be from the collateral branch of the second right intercostal nerve. This supports the theory that these rare muscles may be derived from a single external intercostal muscle which grew to span several intercostal spaces.

Aged↗
PubMed1976

Role of selected muscles of respiration as influenced by posture and tidal volume.

Studies of the activity of accessory respiratory muscles were conducted in 30 normal subjects (15 male and 15 female subjects, age 5 to 62 years). Electromyograms were recorded over the right serratus anterior muscle and the adjacent sixthe intercostal space, and the results were correlated with tidal volume. Phasic respiratory activity in the serratus anterior muscle was detected in every subject but was markedly affected by the prevailing posture and level of ventilation (appearing at mean tidal volumes equivalent to 60.5 percent of vital capacity when subjects were standing relaxed, and equivalent to 35.2 percent of vital capacity when subjects were seated, leaning forward with elbows supported). The activity was predominantly inspiratory in timing but in some subjects extended into early expiration. No significant differences were noted in subjects of different ages, sex, height, or weight. Similar results were recorded from the inspiratory intercostal muscle. On the basis of these findings, we conclude that, contrary to reports, the serratus anterior muscle should be classified as an accessory muscle of respiration, at least at increased levels of ventilation, and that its activity is most pronounced in postures that place the muscles' origin in an advantageous position for moving the ribs.

Adolescent↗