Contraction of the abdominal muscles associated with movement of the lower limb

Background and Purpose. Activity of the trunk muscles is essential for maintaining stability of the lumbar spine because of the unstable structure of that portion of the spine. A model involving evaluation of the response of the lumbar multifidus and abdominal muscles to leg movement was developed to evaluate this function. Subjects. To examine this function in healthy persons, 9 male and 6 female subjects (mean age = 20.6 years, SD = 2.3) with no history of low back pain were studied. Methods. Fine-wire and surface electromyography electrodes were used to record the activity of selected trunk muscles and the prime movers for hip flexion, abduction, and extension during hip movements in each of these directions. Results. Trunk muscle activity occurring prior to activity of the prime mover of the limb was associated with hip movement in each direction. The transversus abdominis (TrA) muscle was invariably the first muscle that was active. Although reaction time for the TrA and oblique abdominal muscles was consistent across movement directions, reaction time for the rectus abdominis and multifidus muscles varied with the direction of limb movement. Conclusion and Discussion. Results suggest that the central nervous st stem deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipation of reactive forces produced by limb movement. The TrA and oblique abdominal muscles appear to contribute to a function not related to the direction of these forces.

National audit of anaesthesia for major abdominal surgery

A postal survey was conducted of all hospitals in Australia known to have a department of anaesthesia and an intensive care or high dependency unit. Each hospital was asked to report the anaesthetic and postoperative analgesic techniques used for the last ten cases of four common major surgical procedures-aorto-femoral bypass, repair of an abdominal aortic aneurysm, hemicolectomy and anterior resection of the rectum. Half of 76 hospitals sent a survey form completed and returned it. Responding hospitals were larger on average, than non-responding ones, but otherwise typical of them in terms of university affiliation and metropolitan versus rural location. For each of the procedures studied the proportion of cases in which epidural block was used intra- or postoperatively varied from 0% to 100%. Depending on the procedure, between 65% and 85% of hospitals used epidural block sometimes, with between 10% and 90% of patients in these hospitals being managed with this technique. There is wide variation in the use of epidural block, intra- and postoperatively, in Australia, variation that is unlikely to be explained by systematic differences between institutions in the patients seen or their suitability for one or other technique. This pattern of practice mirrors the lack of agreement about the proper place for epidural techniques evident in the recent literature. There is a widespread belief among clinicians that this is a question of great importance. Accordingly, we believe that anaesthetists and surgeons share an ethical responsibility to enter suitable patients in an appropriately designed randomized controlled trial in order to resolve this question.

Contractions of specific abdominal muscles in postural tasks are affected by respiratory maneuvers

The influence of respiratory activity of the abdominal muscles on their reaction time in a postural task was evaluated. The electromyographic (EMG) onsets of the abdominal muscles and deltoid were evaluated in response to shoulder flexion initiated by a visual stimulus occurring at random throughout the respiratory cycle. Increased activity of the abdominal muscles was produced by inspiratory loading, forced expiration below functional residual capacity, and a static glottis-closed expulsive maneuver. During quiet breathing, the latency between activation of the abdominal muscles and deltoid was not influenced by the respiratory cycle. When respiratory activity of the abdominal muscles increased, the EMG onset of transversus abdominis and internal oblique, relative to deltoid, was significantly earlier for movements beginning in expiration, compared with inspiration [by 97-107 ms (P < 0.01) and 64-90 ms (P < 0.01), respectively]. However, the onset of transversus abdominis EMG was delayed by 31-54 ms (P < 0.01) when movement was performed during a static expulsive effort, compared with quiet respiration. Thus changes occur in early anticipatory contraction of transversus abdominis during respiratory tasks but they cannot be explained simply by existing activation of the motoneuron pool.

Back, chest and abdominal pain: How good are spinal signs at identifying musculoskeletal causes of back, chest or abdominal pain?

Background: Spinal signs found in association with atypical chest and abdominal pain may suggest the pain is referred from the thoracic spine. However, the prevalence of such signs in these conditions has rarely been compared with that in those without pain. In this study, the prevalence of spinal signs and dysfunction in patients with back, chest and abdominal pain is compared with that in pain free controls. The aim of the study is to determine the significance of spinal findings in patients with such pain. Methods: A general practitioner blinded to the patients' histories performed a cervical and thoracic spinal examination on general practice patients with back, chest and/or abdominal pain and on controls without pain. Thoracic intervertebral dysfunction was diagnosed on the basis of movement and palpation findings. Results: Seventy three study patients plus 24 controls, were examined. For cervical spinal signs, pain in the back, chest and/or abdomen was associated with pain with active movements and overpressure at end range and with loss of movement range. For thoracic spinal signs, this association held for pain with active movements and overpressure, but not with loss of movement range. The prevalence of thoracic intervertebral dysfunction was 25.0% in controls, 65.5% with chest/abdominal pain, 72.0% with back pain and 79.0% with back pain with chest/abdominal pain. This prevalence was higher with chest pain than with abdominal pain. Conclusions: The results show an association, but not a causal link between thoracic intervertebral dysfunction and atypical chest/abdominal pain. A spinal examination should be performed routinely assessing these conditions. The minimum examination for the detection of intervertebral dysfunction is testing for pain with spinal movements and palpation for tenderness. The interpretation of positive signs requires knowledge of their prevalence in pain free controls and in patients with visceral disease

Functional roles of abdominal and back muscles during isometric axial rotation of the trunk

Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis. external oblique. internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles. (C) 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Co-activation of the abdominal and pelvic floor muscles during voluntary exercises

The response of the abdominal muscles to voluntary contraction of the pelvic floor (PF) muscles was investigated in women with no history of symptoms of stress urinary incontinence to determine whether there is co-activation of the muscles surrounding the abdominal cavity during exercises for the PF muscles. Electromyographic (EMG) activity of each of the abdominal muscles was recorded with fine-wire electrodes in seven parous females. Subjects contracted the PF muscles maximally in three lumbar spine positions while lying supine. In all subjects. the EMG activity of the abdominal muscles was increased above the baseline level during contractions of the PF muscles in at least one of the spinal positions. The amplitude of the increase in EMG activity of obliquus externus abdominis was greatest when the spine was positioned in flexion and the increase in activity of transversus abdominis was greater than that of rectus abdominis and obliquus externus abdominis when the spine was positioned in extension. In an additional pilot experiment. EMG recordings were made from the pubococcygeus and the abdominal muscles with fine-wire electrodes in two subjects during the performance of three different sub-maximal isometric abdominal muscle maneuvers. Both subjects showed an increase in EMG activity of the pubococcygeus with each abdominal muscle contraction. The results of these experiments indicate that abdominal muscle activity is a normal response to PF exercise in subjects with no symptoms of PF muscle dysfunction and provide preliminary evidence that specific abdominal exercises activate the PF muscles. Neurourol. Urodynam. 20:31-42, 2001. (C) 2001 Wiley-Liss, Inc.

Beware the boogie board: blunt abdominal trauma from bodyboarding

Riding waves on a bodyboard (boogie board) at the beach is popular with children. Three teenagers who sustained blunt abdominal trauma during bodyboarding are described. Two suffered lacerated livers, one a lacerated spleen. Serious blunt abdominal injuries from bodyboarding mishaps have not previously been reported. The usual method of riding a bodyboard may place the rider at risk of abdominal trauma.

The value of screening in siblings of patients with abdominal aortic aneurysm

Objectives. This study aimed to determine the incidence of abdominal aortic aneurysm (AAA) in a large group of siblings of Australian AAA patients to determine if screening in this group is justified. Methods. 1254 siblings of 400 index AAA patients were identified and offered aortic ultrasound screening. An age and sex matched control group was recruited from patients having abdominal CT scans for non-vascular indications. AAA was defined by an infrarenal aortic diameter of greater than or equal to3 cm or a ratio of the infrarenal to suprarenal aortic diameter of greater than or equal to2.0. A ratio of 1.0-1.5 was considered normal, and a ratio of >1.5 to

Intra-abdominal lipoma in a dog

A 13-year-old Labrador cross dog was presented with progressive abdominal distension of three to four months duration. A large abdominal mass displacing the intestines in a cranio-dorsal direction was diagnosed radiographically. A 4.5kg intra-abdominal lipoma was surgically removed from the lesser omentum near the splenic pedicle. This condition has been infrequently reported in the dog.

Intra-abdominal pressure response to multidirectional support-surface translation

A complex response of the trunk muscles occurs to restore equilibrium in response to movement of the support surface. Intra-abdominal pressure (IAP) is considered to contribute to control of the trunk. This study investigated the contribution of IAP to the postural response to multidirection support-surface translation. IAP was recorded with a thin-film pressure transducer inserted via the nose into the stomach and trunk motion was recorded with an optoelectronic system with markers over the spinous process of L1. A pattern of trunk movement was recorded in response to the support-surface translations that was consistent with a 'hip' strategy of postural control. The trunk moved in a manner appropriate to move the centre of gravity over the new base of support. IAP was increased with movement in each direction, but varied in timing and amplitude between translation directions. In general, the IAP was greater with translations in the sagittal plane compared to the frontal plane and was initiated earlier for translations in the backward direction. These data indicate that IAP contributes to the postural response associated with support-surface translation and suggest that this is consistent with stiffening the spine. (C) 2003 Elsevier B.V. All rights reserved.