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At least 379 records · Page 21Linked to original sources

PubMed2006

Kinematic synergy adaptation to an unstable support surface and equilibrium maintenance during forward trunk movement.

The aim of this investigation was to study the adaptation to an unstable support surface of kinematic synergy responsible for equilibrium control during upper trunk movements. Eight adult subjects were asked to bend their upper trunk forward to an angle of 35 degrees and then to hold the final position for 3 s, first in a standard condition, with two feet on the ground and the second, on a rocking platform swinging in the sagittal plane. The movement characteristics (duration, amplitude, and mean angular velocity of the trunk), the time course of the antero-posterior center of mass (CM) shift during the movement, and the EMG pattern of the main muscles involved in the movement were studied under the two experimental conditions. Kinematic synergy was quantified by performing a principal component analysis on the hip, knee, and ankle angle changes occurring during the movement. The results indicate that (1) the CM shift from the very onset of the movement remains controlled during performance of the forward trunk movement when the equilibrium constraints were increased; (2) the principal component analysis of the hip, knee, and ankle angle changes occurring during the movement showed a transition from one principal component (PC(1)) in the standard condition to two components in the rocking platform condition; (3) the greatest contribution of PC(1) (weight coefficients) was located at the hip level in both the standard and rocking platform conditions, while the greatest contribution of PC(2) in the rocking platform condition was located at the ankle level; and (4) the EMG pattern underlying kinematic synergy is modified. It is concluded that a simple adaptation of kinematic synergy by changing the weight coefficients of each pair of joints participating in the movement is no longer sufficient when the equilibrium constraints increase and, rather, disturbs equilibrium. The CNS has to provide two parallel controls, one to perform the trunk movement and the other to preserve equilibrium.

Adaptation, Physiological↗

PubMed2000

The timing of arm-trunk coordination is deficient and vision-dependent in Parkinson's patients during reaching movements.

The role of the basal ganglia in the coordination of different body segments and utilization of motor synergies was investigated by analyzing reaching movements to remembered three-dimensional (3D) targets in patients with Parkinson's disease (PD). Arm movements were produced alone or in combination with a forward bending of the trunk, with or without visual feedback. Movements in PD patients were more temporally segmented, as evidenced by irregular changes in tangential velocity profiles. In addition, the relative timing in the onsets and offsets of fingertip and trunk motions were substantially different in PD patients than in control subjects. While the control subjects synchronized both onsets and offsets, the PD patients had large mean intervals between the onsets and offsets of the fingertip and trunk motions. Moreover, PD patients showed substantially larger trial-to-trial variability in these intervals. The degree of synchronization in PD patients gradually increased during the movement under the influence of visual feedback. The mean and variability of the intersegmental intervals decreased as the fingertip approached the target. This improvement in timing occurred even though the separate variability in the timing of arm and trunk motions was not reduced by vision. In combined movements, even without vision, the PD patients were able to achieve normal accuracy, suggesting they were able to use the same movement synergies as normals to control the multiple degrees of freedom involved in the movements and to compensate for the added trunk movement. However, they were unable to recruit these synergies in the stereotyped manner characteristic of healthy subjects. These results suggest that the basal ganglia are involved in the temporal coordination of movement of different body segments and that related timing abnormalities may be partly compensated by vision. Abnormal intersegmental timing may be a highly sensitive indicator of a deficient ability to assemble complex movements in patients with basal-ganglia dysfunction. This abnormality may be apparent even when the overall movement goal of reaching a target is preserved and normal movement synergies appear to be largely intact.

Aged↗

PubMed2001

Hepatomesenteric trunk.

An hepatomesenteric trunk, formed by the common hepatic and superior mesenteric arteries, was found in a 50-year-old male cadaver. The left gastric and splenic arteries arose as a common trunk, the gastrosplenic trunk, from the abdominal aorta; no typical celiac trunk was present. In addition, the hepatomesenteric trunk passed posterior to the portal vein. A knowledge of variations of the common hepatic artery may be important in pancreaticoduodenectomy, as well as during hepatic artery infusion chemotherapy.

Arteries↗

PubMed2004

Differential activity of regions of transversus abdominis during trunk rotation.

The role of the abdominal muscles in trunk rotation is not comprehensively understood. This study investigated the electromyographic (EMG) activity of anatomically distinct regions of the abdominal muscles during trunk rotation in six subjects with no history of spinal pain. Fine-wire electrodes were inserted into the right abdominal wall; upper region of transversus abdominis (TrA), middle region of TrA, obliquus internus abdominis (OI) and obliquus externus abdominis (OE), and lower region of TrA and OI. Surface electrodes were placed over right rectus abdominis (RA). Subjects performed trunk rotation to the left and right in sitting by rotating their pelvis relative to a fixed thorax. EMG activity was recorded in relaxed supine and sitting, and during an isometric hold at end range. TrA was consistently active during trunk rotation, with the recruitment patterns of the upper fascicles opposite to that of the middle and lower fascicles. During left rotation, there was greater activity of the lower and middle regions of contralateral TrA and the lower region of contralateral OI. The upper region of ipsilateral TrA and OE were predominately active during right rotation. In contrast, there was no difference in activity of RA and middle OI between directions (although middle OI was different between directions for all but one subject). This study indicates that TrA is active during trunk rotation, but this activity varies between muscle regions. These normative data will assist in understanding the role of TrA in lumbopelvic control and movement, and the effect of spinal pain on abdominal muscle recruitment.

Abdominal Muscles↗

PubMed2005

Trunk muscular activation patterns and responses to transient force perturbation in persons with self-reported low back pain.

Trunk stability requires muscle stiffness associated with appropriate timing and magnitude of activation of muscles. Abnormality of muscle function has been implicated as possible cause or consequence of back pain. This experimental study compared trunk muscle activation and responses to transient force perturbations in persons with and without self-reported history of low back pain. The objective was to determine whether or not history of back pain was associated with (1) altered anticipatory preactivation of trunk muscles or altered likelihood of muscular response to a transient force perturbation and (2) altered muscle activation patterns during a ramped effort. Twenty-one subjects who reported having back pain (LBP group) and twenty-three reporting no recent back pain (NLBP group) were tested while each subject stood in an apparatus with the pelvis immobilized. They performed 'ramped-effort' tests (to a voluntary maximum effort), and force perturbation tests. Resistance was provided by a horizontal cable from the thorax to one of five anchorage points on a wall track to the subject's right at angles of 0 degrees, 45 degrees, 90 degrees, 135 degrees and 180 degrees to the forward direction. In the perturbation tests, subjects first pulled against the cable to generate an effort nominally 15% or 30% of their maximum extension effort. The effort and the EMG activity of five right/left pairs of trunk muscles were recorded, and muscle responses were detected. In the ramped-effort tests the gradient of the EMG-effort relationship provided a measure of each muscle's activation. On average, the LBP group subjects activated their dorsal muscles more than the NLBP group subjects in a maximum effort task when the EMG values were normalized for the maximum EMG, but this finding may have resulted from lesser maximum effort generated by LBP subjects. Greater muscle preactivation was recorded in the LBP group than the NLBP group just prior to the perturbation. The likelihood of muscle responses to perturbations was not significantly different between the two groups. The findings were consistent with the hypothesis that LBP subjects employed muscle activation in a quasi-static task and preactivation prior to a perturbation in an attempt to stiffen and stabilize the trunk. However, interpretation of the findings was complicated by the fact that LBP subjects generated lesser efforts, and it was not known whether this resulted from anatomical differences (e.g., muscle atrophy) or reduced motivation (e.g., pain avoidance).

Adult↗

PubMed1998

The natural history of trunk list, its associated disability and the influence of McKenzie management.

Lumbosacral list is a clinical sign that is frequently associated with low back pain and intervertebral disc lesions. This study examines the influence of McKenzie management on the natural history of trunk list. Patients with trunk list and low back pain were randomised into two groups: a control group receiving non-specific back massage and general back care advice, and a group treated according to the McKenzie protocol. Trunk list was measured over a period of 90 days and patients completed Oswestry Disability Questionnaires. There was a significantly greater resolution of list after 90 days in the group receiving McKenzie treatment compared to the control group. There was poor correlation between list magnitude and Oswestry scores. These data support previous observations that trunk list is not necessarily related to the degree of physical disability. The McKenzie method of assessment and treatment may assist in the resolution of trunk list, but it was ineffective in improving clinical condition.

Adult↗

PubMed2002

Quantitative analysis of the effect of lumbar orthosis on trunk muscle strength and muscle activity in normal subjects.

We studied the effect of lumbar orthosis on trunk muscle strength and muscle activity during flexion-extension bending of the trunk in 31 male volunteers. Trunk muscle strength was measured with a kinetic measurement system. Peak torque was calculated by using the mean torque of five repetitions. Trunk muscle activity was measured with commercially available equipment that has portable EMG data-collection units. The maximum level of the EMG signal was evaluated by employing the analyzing part of the computer's measuring program. With the application of the lumbar orthosis, the strength of the abdominal muscle and the back muscle increased; conversely, the activities of both muscles were decreased significantly. This might imply that lumbar orthosis reduces the load of the trunk muscles during performance.

Adult↗

PubMed1987

Embryonic trunk circumference: a new biometric parameter for estimation of gestational age.

One hundred thirty-one uncomplicated, singleton pregnancies between 7 and 12 weeks of gestation were ultrasonically examined. Evaluation included confirmation of cardiac activity and measurements of fetal crown-rump length and trunk circumference. Both crown-rump length and trunk circumference were curvilinearly correlated with gestational age. A second- and third-degree polynomial equation best described this curvilinear relationship between trunk circumference and gestational age and between crown-rump length and gestational age. The crown-rump length and trunk circumference were similar in their prediction of gestational age, but the combination of the two parameters did not improve the prediction of gestational age. A nomogram of gestational age as predicted by trunk circumference was generated. These data provide an additional measurement for the estimation of gestational age in the first trimester of pregnancy.

Biometry↗

PubMed1985

Trunk position sense in the frontal plane.

Twenty healthy volunteers (ages 18 to 25 years) were tested for their ability to sense the lateral position of the top of their thoracic spine. When moved slowly from side-to-side in the frontal plane with vision occluded and pelvis immobilized, they could sense the position of a midline point on the skin at the T1 level to within 3 mm of a mean center position in relaxed standing tests, and to within 9 mm in supine tests. When subjects centered themselves actively, or additionally, contracted trunk flexor or extensor muscles to predetermined levels of activity, no increase in trunk positioning accuracy was found. The effect of a lateral pelvic tilt or lateral trunk moment had little effect on trunk positioning accuracy, but always induced a characteristic trunk offset. No differences were found in any of these results between males or females, or gymnasts or nongymnasts.

Adolescent↗

PubMed1990

Progesterone metabolism in the microsomal fraction of the testis, head kidney, and trunk kidney from the rainbow trout.

In the present study on male rainbow trout, well-defined microsomal fractions from gonad, trunk kidney, and head kidney were used to study enzymes active on progesterone. The metabolites produced were identified by mass spectrometric analysis. In the testis the main metabolite was 17 alpha-hydroxyprogesterone which is an intermediate in the steroid biosynthetic pathway. 17 alpha-Hydroxyprogesterone was also identified in incubations from head and trunk kidney. The 17 alpha-hydroxylase activity was higher in the head kidney than in the trunk kidney which probably reflects the presence of steroid producing interrenal cells in this part of the kidney. The conversion of progesterone to 17 alpha-hydroxylated products in the testis and head kidney was NADPH dependent and inhibited by carbon monoxide, indicating the participation of cytochrome P450 monooxygenase in this reaction. NADH supported the reaction to some extent (27% of the NADPH-dependent activity) in the testis but not in the head kidney. In addition to 17 alpha-hydroxyprogesterone the head and trunk kidney microsomes gave rise to 16 alpha- and 6 beta-hydroxyprogesterone. These activities were low or absent in testis microsomes. Progesterone 5 alpha-reductase activity was only detected in trunk kidney microsomes.

17-alpha-Hydroxyprogesterone↗

PubMed1995

An EMG-assisted model of trunk loading during free-dynamic lifting.

One of the continuing challenges in biomechanics has been to assess loading of the spine during dynamic lifting exertions. A model was developed to accurately simulate multi-dimensional spinal loads and trunk moments from measured muscle coactivity and external forces during free-dynamic lifting exertions. Model validity was demonstrated by comparing measured and predicted trunk extension moments. Its purpose was to examine realistic representations of lifting kinetics, kinematics, and dynamic trunk mechanics that may influence spinal loading, and to demonstrate that EMG-assisted modeling techniques can be applied to the analysis of free-dynamic exertions. Spinal loads and trunk moments were predicted from the muscle force vectors and external loads. Muscle tensile forces were determined from the product of normalized EMG data modulated to account for contractile dynamics, muscle cross sectional area, and muscle force per unit cross-sectional area. Model output was physiologically valid, i.e. average predicted muscle force per unit cross-sectional area of 50-65 N cm-2, and accurately predicted measured, dynamic, lifting moments, with an average R2 = 0.81 in the sagittal plane and R2 = 0.76 in the lateral plane. Results indicated that compressive and shear loading increased significantly with exertion load, lifting velocity, and trunk asymmetry.

Abdominal Muscles↗

PubMed1984

Intermanual information transfer in patients with lesions in the trunk of the corpus callosum.

Interhemispheric transfer of haptic information was examined in six partially callosotomized patients and three control subjects. Three different portions of the trunk were severed in different subjects. The most anterior 10 mm of the trunk, anterior to the foramen of Monro, was sectioned in one patient. Three other patients had lesions restricted to the anterior part of the trunk posterior to the foramen of Monro. The posterior third of the trunk was damaged in two patients. The splenium, genu and rostrum of the corpus callosum were intact in all six patients, as were the anterior and hippocampal commissures. Poor transfer of haptic information was found only in the three patients with the lesion located in the anterior part of the trunk posterior to the foramen of Monro. The functional anatomy of this region is discussed. It is assumed to house fibers responsible for interhemispheric transfer of complex tactile information.

Adolescent↗

PubMed1993

Quantitative analysis of the cervical sympathetic trunk in young adult and aged rats.

The cervical sympathetic trunk of rats aged 4 and 24 months was examined quantitatively with particular reference to the predominating population of unmyelinated axons by using electron microscope photomontages of transverse sections of the entire nerve trunk. No obvious neuropathological or degenerative changes were observed in animals of either age. At 24 months the mean diameter of unmyelinated axons, the mean number of axons/100 microns2 and the mean number of axons associated with individual Schwann cell units was significantly greater than in the young adult animals. With regard to the small population of myelinated axons in the nerve trunk, the thickness of the myelin sheath did not change with age. The numbers of endoneurial blood vessels in the trunk was not significantly different. This analysis of the cervical sympathetic trunk is consistent with other morphological, histochemical and biochemical evidence which suggests that elements of the cervical sympathetic system are well preserved in aged rats.

Aging↗

PubMed1990

Morphometric data concerning the great arterial trunks and their branches.

In a total of 496 fetuses and newborns ranging in body weight from 60 to 5000 g, we performed a morphometric study of the vascular complex, that is the orifices of the great arterial trunks, ascending aorta, aortic arch, vessels branching from the aortic arch, the aortic isthmus, descending aorta, pulmonary trunk, orifices of the pulmonary arteries and arterial duct. In all, 17 different parameters were measured in each specimen, using several new parameters in addition to the measurements classically used in the aortic isthmus, arterial duct and pulmonary trunk. Anatomo-geometric models of these structures were developed, and stereometric formulas used to calculate the real volumes of the aortic isthmus, arterial duct and pulmonary trunk. The variations in the correlations between two measurable characteristics, that is, body weight and each of the morphometric parameters were analyzed, and the minimum, normal and maximum patterns of normality for each parameter were obtained with regression equations. The results show that the volume of the aortic isthmus increases by 0.03 ml for each millilitre increase in left ventricular volume. The isthmic volume increases by 0.32 ml for each millilitre increase in volume of the arterial duct and the volume of the pulmonary trunk increases by 6.4 ml for each increase of 1 millilitre in the volume of the aortic isthmus. The inner circumference of the aortic isthmus is greater than that of the arterial duct, whereas the former vessel is always shorter than the latter. We believe that these morphological data, when appropriately interpreted, have immediate clinical and surgical applications in the treatment of fetal and perinatal cardiovascular disorders.

Aorta↗

PubMed1984

The effect of previous transection on quantitative estimates of the preganglionic neurones projecting in the cervical sympathetic trunk of the guinea-pig and the cat made by retrograde labelling of damaged axons by horseradish peroxidase.

The numbers of sympathetic preganglionic neurones in the upper thoracic spinal cord retrogradely labelled after application of horseradish peroxidase to the severed axons of the cervical sympathetic trunk have been determined in guinea-pigs and in cats. Neuronal counts were made on both sides of spinal segments C8 to T10 in control animals and in others in which the enzyme was applied 5-8 days after the left cervical sympathetic trunk had been transected. Labelling was not significantly different between sides of unoperated animals, but after previous cervical trunk section labelling was always less, by from 5 to 100% of that on the control side. The results were not significantly different if the application of horseradish peroxidase was made close to the original lesion or 1 cm more proximal along the nerve trunk. Analysis of the dimensions of labelled cells suggested that the deficit in labelling was greatest for small preganglionic neurones. These findings do not support an earlier report that retrograde labelling from regenerating axons is enhanced at this stage after axotomy, and the possible reasons for the discrepancy in results are discussed. It is suggested that labelling of cell bodies may not be restricted if intact axon sprouts are exposed to horseradish peroxidase. Reduced labelling from axons at the time of a second transection might, at least in part, be due to axon atrophy, emphasizing limitations to labelling when horseradish peroxidase is applied to severed axons of fine diameter. The high numbers and reproducibility of our control data enabled estimates to be made of the segmental distribution of the cell bodies or origin of the axons of the cervical sympathetic trunk in both species.

Animals↗

PubMed1995

Muscle power, sitting unsupported and trunk rotation in pre-term infants.

Discrepancies between active and passive muscle power are often seen in pre-term infants over the first year. Generally of a transient nature, they are most obvious in the extensor muscles of the trunk where there is a high active muscle power relative to the passive component. While high active muscle power may not be a sign of cerebral palsy, it is our contention that it will impair functions such as unsupported sitting and the ability to rotate in this position. In this study, 20 full-term and 37 healthy pre-term infants were assessed at the (corrected) ages of 39 and 52 weeks for muscle power in the trunk, sitting unsupported and rotation around the body axis while seated. At the age of 39 weeks, all full-term infants could sit without support. In contrast half of the pre-term infants could not sit without support and the majority of them could not rotate the trunk in this position. At 52 weeks the majority of pre-term infants could sit without support, despite having higher active muscle power in the trunk. However this deviant muscle power prevented rotatory movements of the trunk during sitting. The origin of this deviance may reside in the positioning to which pre-term infants are subjected after birth and thus postural management should be directed towards avoidance of extensor positions.

Adolescent↗

PubMed1990

Is banding of the pulmonary trunk obsolete for infants with tricuspid atresia and double inlet ventricle with a discordant ventriculoarterial connection? Role of aortic arch obstruction and subaortic stenosis.

Banding the pulmonary trunk may exacerbate or promote the development of subaortic stenosis in patients with double inlet ventricle or tricuspid atresia with a dominant left ventricle and discordant ventriculoarterial connection and, therefore, may be an inappropriate palliative procedure for such patients. To examine this possibility, 102 consecutive infants were studied who presented with this anatomy between 1972 and 1987. Obstruction of the aortic arch was present in 52 patients. In 28 patients (17 with aortic arch obstruction), subaortic stenosis was already apparent at presentation. Of the remaining 74 patients, 19 received no palliative surgery and 55 underwent banding of the pulmonary trunk either with (n = 22) or without (n = 33) aortic arch repair. Outcome was significantly worse in patients with associated aortic arch obstruction. All such patients either died or developed subaortic stenosis by 3 years of age (survival free of subaortic stenosis 0 of 22 versus 22 of 33 for patients with isolated banding of the pulmonary trunk, p less than 0.001). After isolated banding, there was a lower ratio of the ventricular septal defect to ascending aorta diameters at presentation in the patients who developed subaortic stenosis than in the patients who did not (0.60 +/- 0.08 versus 1.03 +/- 0.15, p less than 0.001). Of the latter, 18 (95%) of 19 patients fulfilled criteria for a Fontan procedure at recatheterization. Thus, the presence of aortic arch obstruction is associated with rapid development of subaortic stenosis after banding of the pulmonary trunk. Alternative initial surgery, even though high risk, may be indicated. In the absence of such obstruction, banding the pulmonary trunk can be performed at reasonable risk and, provided that the ventricular septal defect is of adequate size, satisfactorily prepares most patients for a later Fontan procedure.

Aortic Arch Syndromes↗

PubMed2004

Dynamic analysis of trunk flexion after stroke.

OBJECTIVE: To quantify trunk movement and lower-extremity weight bearing in patients with stroke-associated hemiparesis compared with healthy subjects. DESIGN: Controlled study with 2 groups: persons with hemiparesis and healthy controls. SETTING: Geriatric center offering rehabilitation services. PARTICIPANTS: A convenience sample of 15 persons with poststroke hemiparesis (age, 69.4+/-12.0y; > or =3mo poststroke; total motor function range, 63-95/100) on the Fugl-Meyer Assessment and of 13 healthy persons (age, 67.8+/-7.5y). INTERVENTIONS: Subjects were seated on a chair placed on a forceplate with their feet on 2 additional forceplates. A target was placed directly in front of or at a 45 degrees angle from the midline at 66% of the nonparetic/dominant arm length. Subjects' task was to touch the target with their forehead. Main outcome measures Amplitude and speed of trunk movements, displacement of the global center of pressure (COP), and percentage of body weight distributed on the buttocks and the feet. RESULTS: Despite speed and amplitude comparable to that of the healthy subjects (NS), subjects with hemiparesis (HS) had less COP displacement (HS, 33.7+/-6.9; NS, 40.5+/-9.2), resulting in a lower weight-bearing value on the feet (HS for the paretic foot, 2.3%+/-3.6%; HS for the nonparetic foot, 2.2%+/-2.9%; NS for the nondominant foot, 5.4%+/-3.4%; NS for the dominant foot, 5.2%+/-4.0%). CONCLUSIONS: The similar amplitude of trunk flexion with a decreased displacement of COP and a lower weight bearing on the feet suggest smaller anterior displacement of the body mass. It is possible that trunk movements in persons with hemiparesis are executed by the upper trunk with very little anterior tilt of the pelvis.

Aged↗