SEARCH · PubMed Health

Results for “Abdominal Muscles”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 19 recordsLinked to original sources

PubMed1989

[Respiratory pattern and activity of the abdominal muscles after upper abdominal surgery].

Because only few data is as yet available concerning abdominal muscle activity following upper abdominal surgery, the present study aimed to investigate the pattern of abdominal muscle activity before and after upper abdominal surgery and to relate any changes to differences in abdominal respiratory movements. Eight ASA I patients (5 women, 3 men), mean age 44 +/- 12 yr, undergoing elective cholecystectomy (midline incision) were investigated. The following parameters were measured, with the patients supine and at rest, on the eve of surgery, and 2, 4, 24 and 72 h afterwards: tidal volume (VT), breathing rate (f), inspiratory time (TI), total cycle time (TT), changes in abdominal (Dab) and thoracic (Drc) circumferences, surface electromyograms of the rectus abdominis and obliquus externus abdominis muscles. The ratio (Dab/Dab + Drc) was used as an index of relative abdominal movement. Anaesthetic management was similar for all patients (thiopentone, fentanyl, vecuronium, halothane and N2O). A significant reduction in VT was found between 2 and 24 h postoperatively, with a significant increase in f between 4 and 24 h after surgery. Both these parameters returned to normal values at the 72nd h. Relative abdominal movement was reduced in the immediate postoperative period (2 and 4 h), slowly improving, but remaining lower than normal at 72 h. Muscle tonus was increased at 2 h and returned to normal at the 4th h. This transient increase suggested a residual effect of fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗

PubMed1987

Activity of lower intercostal and abdominal muscle after upper abdominal surgery.

The decrease in end-expiratory lung volume after upper abdominal surgery has been attributed, in part, to reflex spasm of the abdominal muscles. To examine the influence of abdominal surgery on abdominal muscle tone, electromyographic (EMG) activity of abdominal and lower intercostal muscle was compared before operation with that at 3 hr and at 24 hr after operation in 18 healthy patients undergoing elective gastric or biliary surgery. After operation, EMG activity increased markedly and showed a phasic pattern of activity associated with respiration in most patients. This was characterized by a progressive increase in EMG activity during expiration with an abrupt decrease at the onset of inspiration. We conclude that increased expiratory activity in abdominal and lower intercostal muscle may be responsible for the decrease in lung volumes that occurs after upper abdominal surgery.

Abdomen↗

PubMed1989

Mechanical response to hyperinflation of the two abdominal muscle layers.

Abdominal muscle length changes and activity were directly examined in vivo with the use of the techniques of sonomicrometry and electromyography, respectively, in nine supine anesthetized dogs. Expiratory threshold loading was utilized to stimulate recruitment of the abdominal muscles, and lung inflations produced the passive relationships. The internal layer, consisting of the internal oblique and transversus abdominis, shortened more in expiration than the external layer, consisting of the external oblique and rectus abdominis. The internal oblique shortened to approximately 83% of its length at functional residual capacity vs. 98% for the external oblique (P less than 0.05). The results obtained during passive lung inflation indicate these internal muscles are also more influenced by changes in lung volume. The internal oblique lengthened to 115% of its length at functional residual capacity vs. 103% for external oblique at total lung capacity (P less than 0.05). The results suggest that anatomic division of the abdominal muscles into external and internal layers corresponds to functional differences in terms of both passive lengthening and active shortening during ventilation and that these differences imply variable functions of the two layers.

Abdominal Muscles↗

PubMed1989

Intercostal and abdominal muscle afferent influence on caudal medullary expiratory neurons that drive abdominal muscles.

Our objective was to determine if caudal ventral respiratory group (VRG) expiratory (E) neurons that drive abdominal expiratory motoneurons in the lumbar cord respond to intercostal and lumbar nerve afferent stimulation. Results showed that 92% of medullary E-neurons that were antidromically activated from the upper lumbar cord reduced their activity in response to stimulation of external and internal intercostal and lumbar nerve afferents. We conclude that afferent information from intercostal and abdominal muscle tendon organs has an inhibitory effect on caudal VRG E-neurons that drive abdominal expiratory motoneurons.

Abdominal Muscles↗

PubMed1976

Electromyographic evaluation of human detrusor muscle activity in relation to abdominal muscle activity.

Simultaneous electromyographic (EMG) recordings from the bladder detrusor muscle and the inferior rectus abdominis muscle were made in six normal subjects, in four patients with lower motor neuron bladder disease and in two patients with an upper motor neuron type of bladder lesion. Results of the study demonstrate that the bladder electrodes do not record remote muscle activity from the abdominal muscles so that any increased detrusor electrical activity with abdominal contraction must have some other explanation such as a possible abdominal-detrusor reflex or the production of increased intra-abdominal pressure from abdominal contraction. The study also demonstrates that the detrusor EMG is of value in studying the physiology of the bladder in humans, is a safe and simple technique and is of value particularly in assessing neurogenic bladder disorders.

Abdominal Muscles↗

PubMed1989

Abdominal muscle activity and intraabdominal pressure after upper abdominal surgery.

To examine the influence of abdominal muscle activity on intraabdominal pressure, the integrated surface EMG from upper abdominal muscle (EAB) was related to changes in intragastric pressure (PGA) in six patients after upper abdominal surgery. A similar respiratory pattern of EMG activity was observed in all subjects. EAB increased rapidly at the onset of expiration, and thereafter more slowly throughout expiration. At the onset of inspiration EAB decreased abruptly, and was small during inspiration. Changes in intragastric pressures were closely related to changes in EAB. In five patients PGA and EAB waveforms were almost identical over the respiratory cycle. In one subject a biphasic change in PGA during inspiration was observed, suggesting the influence of other respiratory muscles. Abdominal muscle action results in changes in intraabdominal pressure previously attributed to diaphragmatic impairment.

Abdomen↗

PubMed1987

The abdominal muscles and vertebral stability.

It has been suggested that the muscles of the anterolateral abdominal wall increase the stability of the lumbar region of the vertebral column by tensing the thoracolumbar fascia and by raising intra-abdominal pressure. In this report these new mechanisms are reviewed and their contribution to vertebral stability assessed. The thoracolumbar fascia consists of two principal layers of dense fibrous tissue that attach the abdominal muscles to the vertebral column. Each of these layers was dissected in fresh and fixed material and samples chosen for light and scanning electron microscopy to study the arrangement of the component fibers. Computed axial tomography in volunteers showed the changes in spatial organization that occur during flexion of the back and during the Valsalva maneuver. The fascia was then tensed experimentally in isolated unfixed motion segments. The results suggested that the stabilizing action of the thoracolumbar fascia is less than had been thought previously but was consistent with calculations based on the more accurate structural and mechanical information that had been derived from the current study. Abdominal muscle contraction was simulated in whole cadavers in both the flexed and lateral bending positions to compare the stabilizing effect of the thoracolumbar fascia and intra-abdominal pressure mechanisms. These definitive experiments showed that the resistance to bending in the sagittal plane offered by the abdominal muscles acting through fascial tension was of a similar magnitude to that offered by a raised intra-abdominal pressure, both being relatively small in the fully flexed position. The stabilizing influence of the middle layer of the thoracolumbar fascia in lateral bending was clearly demonstrated and warrants further study in vivo.

Abdominal Muscles↗

PubMed1987

Localization of motoneurons innervating individual abdominal muscles of the cat.

The motor pools of the individual abdominal muscles of the cat were localized in studies by using either intramuscular injections of horseradish peroxidase (HRP) to retrogradely label abdominal motoneurons or electrical microstimulation of the ventral horn at different segmental levels to produce localized twitches of the abdominal muscles. The segmental distribution of each motor pool was as follows: rectus abdominis, T4-L3; external oblique, T6-L3; transverse abdominis, T9-L3; and internal oblique, T13-L3. The differences in the rostral extents of the individual motor pools reflect the greater rostral extents of the different muscles (rectus abdominis greater than external oblique greater than transverse abdominis greater than internal oblique). Labeled motoneurons were also found at other segmental levels; however, it was concluded that this labeling occurred because of spread of HRP from the injected muscle since localized abdominal muscle twitches could not be produced by electrical stimulation in these regions. In addition, control experiments showed that HRP can spread from the injected muscle and identified the sources of some of this spurious labeling. Motoneurons labeled after injections into the four abdominal muscles overlapped extensively on transverse sections of the spinal cord; however, rectus abdominis motoneurons were located more medially than the others from about T11 to L3. Soma diameters ranged between 12 and 41 microns (average 24-26 microns per cat). In summary, this study has provided a systematic description of the innervation of the individual abdominal muscles of the cat.

Abdominal Muscles↗

PubMed1991

Abdominal muscle activity during CO2 rebreathing in sleeping neonates.

Comparison of the abdominal muscle response to CO2 rebreathing in rapid-eye-movement (REM) and non-REM (NREM) sleep was performed in healthy premature infants near full term. Eight subjects were studied at a postconceptional age of 40 +/- 1.6 (SD) wk (range 38-43 wk) during spontaneous sleep. Sleep stages were defined on the basis of electrophysiological and behavioral criteria, and diaphragmatic and abdominal muscle electromyographic activity was recorded by cutaneous electrodes. The responses to CO2 were measured by a modified Read rebreathing technique. The minute ventilation and diaphragmatic and abdominal muscle electromyographic activities were calculated and plotted against end-tidal CO2 partial pressure. Both the ventilatory and diaphragmatic muscle responses to CO2 decreased from NREM to REM sleep (P less than 0.05). Abdominal muscles were forcefully recruited in response to CO2 rebreathing during NREM sleep. In REM sleep, abdominal muscle response to CO2 was virtually absent or decreased compared with NREM sleep (P less than 0.05). We conclude that 1) the abdominal muscles are recruited during NREM sleep in response to CO2 rebreathing in healthy premature infants near full term and 2) the abdominal muscle recruitment is inhibited during REM sleep compared with NREM sleep, and this REM sleep-related inhibition probably contributes to the decrease in the ventilatory response to CO2 rebreathing in REM sleep.

Abdomen↗

PubMed1990

Mechanisms of abdominal muscle activation during vomiting.

The possible contribution of spinal reflexes to abdominal muscle activation during vomiting was assessed in decerebrate cats. The activity of these muscles is partly controlled by bulbospinal expiratory neurons in the caudal ventral respiratory group (VRG). In a previous study it was found that the abdominal muscles are still active during vomiting after midsagittal lesion of the axons of these neurons between C1 and the obex (A.D. Miller, L.K. Tan, and I. Suzuki. J. Neurophysiol. 57: 1854-1866, 1987). The present experiments indicate that this postlesion activity was due to spinal stretch reflexes because 1) such midsagittal lesions eliminate abdominal muscle nerve activity during fictive vomiting in paralyzed cats in which there are no abdominal stretch reflexes, 2) the abdominal muscles are activated during vomiting by spinal reflexes after upper thoracic cord transections, and 3) the normal 100-ms delay between diaphragmatic and abdominal activation during vomiting is reduced to approximately 20-25 ms after both types of lesions, which is consistent with postlesion abdominal reflex activation. Our results also suggest that, during normal vomiting, abdominal stretch and tension reflexes have only a minor role if any and abdominal muscle activation is probably mediated primarily or exclusively by expiratory neurons in the caudal ventral respiratory group. However, our finding that phrenic activity is reduced both during vomiting after thoracic transections and during fictive vomiting after paralysis is consistent with a contribution of reflex activity from abdominal and/or intercostal muscles to phrenic discharge during normal vomiting.

Abdominal Muscles↗

PubMed1979

Urethral obstruction malformation complex: a cause of abdominal muscle deficiency and the "prune belly".

Abdominal muscle deficiency with a "prune belly" abdomen as been a major feature of the so-called prune belly syndrome, which has been regarded as a specific entity, although the etiology and developmental pathology are not understood. We present evidence that abdominal muscle deficiency is an etiologically nonspecific anatomic defect which is secondary to fetal abdominal distention of various causes. One of the more common causes is urethral obstruction with consequent early bladder distention, causing abdominal distention and other anomalies, a constellation of findings which we have termed the urethral obstruction malformation complex. This interpretation of the etiology of most cases of prune belly syndrome accounts for the male predominance, the observed variability in severity, and the lack of a defined mode of inheritance. Recurrence risk figures need to be redefined for each specific obstructing lesion of the urethra. The possibility of early prenatal diagnosis and management of fetuses with urethral obstruction needs further study.

Abdominal Muscles↗

PubMed1990

Expiratory abdominal muscle activity during ventilatory chemostimulation in piglets.

We examined abdominal muscle minute electromyographic (EMG) activity (peak moving time average EMG x respiratory rate) during eupnea, hyperoxic hypercapnia (8% CO2-40% O2-balance N2), and hypoxia (13% O2) in 12 anesthetized (0.5% halothane) newborn piglets. In addition, we assessed the role of vagal afferent pathways in the abdominal muscles' response to ventilatory chemostimulation by examining abdominal EMG activity (EMGab) before and after bilateral cervical vagotomy in five animals. Phasic expiratory EMGab was observed in 11 of 12 piglets during eupnea. Hypercapnia was associated with a sustained augmentation of minute EMGab (444 +/- 208% control). In contrast, hypoxia consistently augmented (1 min, 193 +/- 33% control) then diminished (5 min, 126 +/- 39% control) minute EMGab. Vagotomy resulted in a decline in peak moving time average EMGab by approximately one-half (48 +/- 18% control); the abdominal muscles' response to ventilatory chemostimulation, however, was qualitatively unchanged. We conclude that 1) expiration during eupnea in anesthetized newborn piglets is associated with phasic EMGab; 2) both hypercapnia and hypoxia augment minute EMGab; however, only hypercapnia is associated with sustained augmentation; and 3) although vagal afferents have a role in modulating the base-line level of EMGab, other extravagal mechanisms appear to determine the pattern of EMGab in response to ventilatory chemostimulation.

Abdominal Muscles↗

PubMed1989

Sleep-related abdominal muscle behavior during partial or complete obstructed breathing in prepubertal children.

We have evaluated the influence of nonrapid eye movement (NREM), REM sleep, and arousal on abdominal muscle contractions during snoring and/or obstructive apnea in 10 prepubertal children. All children were known habitual snorers and eight had a sleep apnea index above 10. During stage 3-4 non-REM sleep, non-apneic breathing with snoring was always associated with the presence of expiratory abdominal muscle electromyogram (EMG) discharges. During non-REM sleep apneas, abdominal muscle EMG discharges increased from the beginning to the end of each apnea. Termination of non-REM sleep apnea was marked by an "EEG arousal" in 12% of the apneic events and by a "movement arousal" in the other 88%. The highest abdominal muscle EMG discharge was always observed during the arousal response. During "phasic" REM sleep, abdominal muscle EMG discharges were absent during both nonapneic breathing (with or without snoring) and obstructive apneas. All REM sleep apneas ended with a "movement arousal," during which abdominal muscle EMG discharges were observed. Thus, abdominal muscle EMG discharges associated with "arousal" were seen independent of the immediately preceding sleep state.

Abdominal Muscles↗

PubMed1989

Comparison of human motor cortical projections to abdominal muscles and intrinsic muscles of the hand.

Percutaneous electrical stimulation of the motor cortex was used to activate rapidly conducting corticofugal pathways to human abdominal muscles. Following cortical stimulation the response latencies for the abdominal muscles were similar to those for limb muscles which are a similar distance from the motor cortex. Cortically evoked responses recorded from the abdominal muscles had the same latency and similar amplitude during several voluntary tasks including expiration, expulsive manoeuvres and trunk flexion. Responses could also be evoked when the chemical drive to breathe was increased by rebreathing. In addition, the properties of the cortical projection to muscles of the abdominal wall were directly compared with those of the projection to the intrinsic muscles of the hand. The latencies of responses in abdominal muscles and intrinsic muscles of the hand were measured during static contractions over a range of strengths in the same subjects (0-100% maximal voluntary contraction, MVC). For both muscle groups, cortically evoked muscle responses of minimal latency occurred when background contractions reached 10-20% MVC with responses of maximal amplitude at 60% MVC. The variability in latency of fifty consecutive responses were similar for the two muscle groups. Furthermore, post-stimulus time histograms for 4 rectus abdominis motoneurones revealed a brief initial excitatory peak of 1.15 ms duration (range 0.96-1.34 ms) following cortical stimulation. The characteristics of this peak are the same as reported for motoneurones of intrinsic hand muscles. These findings demonstrate a powerful rapidly conducting pathway from the motor cortex to the human abdominal muscles. This pathway has many of the same properties as the monosynaptic corticospinal projection to the distal muscles of the upper limb.

Abdominal Muscles↗

PubMed1976

Vagal afferents essential for abdominal muscle activity during lung inflation in cats.

Maintained inflation of the lung evokes abdominal muscle activity in anesthetized cats only if the vagus nerves are intact, indicating the importance of vagal receptors. The location of these receptors was determined in 14 anesthetized cats by comparing prevagotomy inflation responses of the abdominal muscles and diaphragm to the responses obtained after section of the thoracic vagi at one of three different levels. The abdominal muscle and diaphragm responses to maintained lung inflation persisted following vagotomy below the roots of the lung or denervation of the heart and great vessels. Denervation at the root of the lung, however, abolished the abdominal muscle response and the Hering-Breuer inflation reflex of the diaphragm. It is concluded that pulmonary receptors are essential for the abdominal expiratory activity, but vagal receptors in the abdomen, esophagus, trachea, heart and great vessels are not.

Abdominal Muscles↗

PubMed1990

Low-back pain in pregnancy. Abdominal muscles, sit-up performance, and back pain.

An attempt was made to determine the effect of pregnancy on the abdominal muscles and to correlate changes in abdominal muscles strength with low-back pain during pregnancy. The study included 328 women. Group A consisted of 164 pregnant women; group B consisted of 164 non-pregnant women. The race, age, height, weight, parity, profession, time devoted to physical fitness per week, abdominal length, and relation between the abdominal length to height were recorded. A detailed history relating to backache prior to and during pregnancy was obtained. Each woman was asked to perform a single sit-up. The results of the study indicate that about 10% of pregnant women develop severe low-back pain that interferes with daily life activities. About 49% of the non-pregnant women complained of LBP. The pain did not interfere with activities of daily living. During pregnancy, due to overstretching of the abdominal muscles, the ability to perform a sit-up is significantly decreased. Whereas all non-pregnant women could perform a sit-up, 16.6% of pregnant women could not perform a single sit-up. There was no statistically significant correlation between the sit-up performance and backache. It may be concluded that during pregnancy the abdominal muscles become insufficient.

Abdomen↗

PubMed1987

Relationships between lumbar lordosis, pelvic tilt, and abdominal muscle performance.

The purpose of this study was to examine the relationships between measurements of lumbar lordosis, pelvic tilt, and abdominal muscle performance during normal standing. In addition, the reliability of the measurements used in this study was examined. Measurements of lumbar lordosis, pelvic tilt, and abdominal muscle performance were taken of 31 healthy adults aged 20 to 33 years. Each measurement was taken twice, and the measurements were shown to be reliable. The Spearman's rho correlation of the abdominal muscle performance measurements with pelvic tilt was .18 and with lordosis was .06. The Pearson product-moment correlation of lordosis with pelvic tilt was .32. The results indicate that lumbar lordosis, pelvic tilt, and abdominal muscle function during normal standing are not related. This study demonstrates the need for a reexamination of clinical practices based on assumed relationships of abdominal muscle performance, pelvic tilt, and lordosis.

Abdominal Muscles↗

PubMed1988

An EMG analysis on regulation of the diaphragm and abdominal muscles.

Neural mechanisms regulating activities of diaphragm and abdominal muscles were investigated on anesthetized, tracheostomized and spontaneously breathing dogs. EMGs of costal diaphragm and external oblique (EO)abdominal muscle were recorded by fine-wire electrodes. The electrodes for diaphragm-EMG were implanted without opening abdominal cavity using laparoscopy. During quiet breathing the mean firing frequency of diaphragm-EMG was 7.6 +/- 0.7 (S.D.) Hz. The discharge spikes of diaphragm-EMG observed in early-inspiration or in post-inspiratory phase, were low in amplitudes, consistent with previous reports that phrenic motoneurons were comprised of two populations. During quiet breathing spikes were not observed in EO-EMG in a half of the animals, and were tonically-firing in the remaining dogs. Hypercapnia increased firing frequency of diaphragm-EMG, but did not recruit spikes of high amplitude. On the other hand, hypercapnia recruited EO-spikes of higher amplitude, and increased firing frequency. When spikes fired tonically in EO-EMG, hypercapnia suppressed these spikes during inspiration. Airway occlusion gradually recruited EO units of higher amplitude. Mechanical stimulation of upper airway suppressed tonic-EO activity during inspiration. In conclusion, we demonstrated that 1) abdominal wall is not related with control mechanism of diaphragm; 2) the control mechanism of dog's EO differs from cat's internal intercostal muscles; and 3) the tonic component of EO is affected by respiratory commands from higher neuronal architecture.

Abdominal Muscles↗