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PubMed1985

Effect of trunk load on the energy expenditure of treadmill walking and ergometer cycling.

Data concerning the effect of trunk loads on the energy expenditure of various activities are scanty and partly conflicting. The energy expenditure of walking (4.5 km hr-1, 1.5% inclination) and ergometer cycling (60 watt, 60 rpm) was measured in 23 apparently healthy subjects with and without a trunk load of 10% of the body weight. For walking, the increment in energy expenditure per kg of load was 2.55 +/- 0.25 watt, while the increment per kg of body weight was 4.01 +/- 0.45 watt. For ergometer cycling, the increment per kg of load was 1.12 +/- 0.64 while that per kg of body weight was 2.73 +/- 0.56 watt. Prediction of energy expenditure for trunk loads has previously been made on the basis of the relation between energy expenditure and body weight. Our data show that this may lead to considerable overestimation.

Adult↗

PubMed1994

Paradoxical variation of strength determinants with different rotation axes in trunk flexion and extension strength tests.

The aim of this study was to illustrate the influence of different levels of the fulcrum (the axis of sagittal rotation) on measured trunk flexion and extension strength and compare force and torque as a unit of measure. The isometric trunk strength was measured in 16 healthy female subjects. The dynamometer was kept at the shoulder level and the moment arm was lengthened step by step by moving the fulcrum caudally from the level of the posterior superior iliac spine to the level of the gluteal fold. The moment of force (torque) increased from 117.0 to 208.5 N.m in flexion and from 182.2 to 292.5 N.m in extension, P < 0.0001. An attempt to quantify this change was made. Paradoxically, the measured force remained at a constant level (in flexion) or slightly decreased (in extension). We concluded that torque as a measure of trunk flexion and extension strength is highly dependent on the level of the rotation axis and force appears to be less sensitive for variations with the height of the fulcrum. We would suggest that the observed increase in torque is physiological and reflects to what extent hip flexor or extensor muscles are recruited. The force, on the other hand, may better characterize a person's capability to perform functional tasks. Force and torque should strictly be distinguished from one another.

Abdomen↗

PubMedDate not supplied

Anomalous origin of the left coronary artery from the pulmonary trunk and its relationship with the morphology of the cardiac semilunar valves in Syrian hamsters.

The conditions of the aortic and pulmonary valves and the arrangement in the origin of the coronary arteries were studied in 247 Syrian hamsters belonging to a single family subjected to high endogamous pressure. Most specimens (n = 216) were examined using a stereomicroscope. The remaining 31 were studied histologically. In 110 specimens both cardiac semilunar valves were normal. The aortic valve was bicuspid and the pulmonary valve was normal in 79 animals, while a normal aortic valve and a bicuspid pulmonary valve occurred in 37. In the remaining 21 specimens both semilunar valves were bicuspid. In 34 cases, the left coronary artery originated from the pulmonary trunk. Statistical analyses indicate that there is no significant relationship between the bicuspid condition of the pulmonary valve and the fact that a coronary artery arises from the pulmonary trunk. On the other hand, they substantiate that the frequency of this coronary artery anomaly significantly increases when the aortic valve is bicuspid. The present findings agree with the hypothesis that abnormal migration of the neural crest cells may be responsible for the combined occurrence of bicuspid aortic valve and anomalous origin of the left coronary artery from the pulmonary trunk. In addition, they suggest that the neural crest cells involved in the formation of the pulmonary valve diverge from those migrating into the aortic valve and those imposing spatial order upon the development of the proximal coronary arteries.

Animals↗

PubMed1994

Imaging myelinated nerve fibres by confocal fluorescence microscopy: individual fibres in whole nerve trunks traced through multiple consecutive internodes.

Current methods of morphological analysis do not permit detailed imaging of individual myelinated fibres over substantial lengths without disruption of neighbouring, potentially significant, cellular and extracellular relationships. We report a new method which overcomes this limitation by combining aldehyde-induced fluorescence with confocal microscopy. Myelin fluorescence was intense relative to that from other tissue components, enabling individual myelinated nerve fibres to be traced for distances of many millimeters in whole PNS nerve trunks. Image obtained with a Bio-Rad MRC-600 confocal laser scanning microscope clearly displayed features of PNS and CNS myelinated fibres including nodes of Ranvier; fibre diameter; sheath thickness and contour; branch points at nodes; as well as (in the PNS) Schmidt-Lanterman incisures and the position of Schwann cell nuclei. Direct comparisons using the same specimens (whole nerve trunks; also teased fibres) showed confocal imaging to be markedly superior to conventional fluorescence microscopy in terms of contrast, apparent resolution and resistance to photobleaching. Development of the fluorophore was examined systemically in sciatic nerves of young adult rats. In separate experiments, animals were perfused systemically using (1) 5% glutaraldehyde; (2) Karnovsky's solution; (3) 4% paraformaldehyde; buffered with either 0.1 M sodium phosphate or sodium cacodylate (pH 7.4). The concentration of glutaraldehyde in the fixative solution was the principal determinant of fluorescence intensity. Confocal imaging was achieved immediately following perfusion with 5% glutaraldehyde or Karnovsky's. Fluorescence intensity increased markedly during overnight storage in these fixatives and continued to increase during subsequent storage in buffer alone. The fluorophore was stable and resistant to fading during storage (15 months at least), enabling data collection over extended periods. To demonstrate application of the method in neuropathology, individual fibres in transected sciatic nerve trunks were traced through multiple successive internodes: Classical features of Wallerian degeneration (axonal swelling and debris; ovoid formation and incisure changes; variation among fibres in the extent of degeneration) were displayed. The method is compatible with subsequent ultrastructural examination and will complement existing methods of investigation of myelinated fibre anatomy and pathology, particularly where preservation of 3-dimensional relationships or elucidation of spatial gradients are required.

Animals↗

PubMed1996

Surgical approaches for vertebro-basilar trunk aneurysms located in the midline.

Fourteen cases of midline vertebro-basilar trunk aneurysms were operated on by four routes of surgical approach: middle fossa anterior transpetrosal approach (ATP), presigmoid transpetrosal approach (PTP), conventional lateral suboccipital approach (LSO) or suboccipital transcondylar approach (STC). There was no mortality, but the morbidity was different depending on the surgical approach. In basilar trunk aneurysms located higher than the internal auditory canal, excellent results were obtainable by ATP, especially in the case of posteriorly projecting aneurysms. For midline vertebral aneurysms located lower than the internal auditory canal, STC resulted in less surgical complications than LSO. Extradural resection of the jugular tubercle was necessary for aneurysms located on the distal vertebral artery at or close to the vertebro-basilar junction. For vertebro-basilar junction aneurysms located at the level of the internal auditory canal, hearing was preserved by STC, but not by ATP or PTP. However, choice of the surgical approach may depend on the direction of the aneurysm and the technical accessibility of the skull base. All these skull base approaches reduced surgical complications of retraction damage to the cranial nerves and the brain stem. This holds true for all aneurysms arising from the midline vertebro-basilar trunk.

Adult↗

PubMed2001

Biomechanical analysis of movement strategies in human forward trunk bending. I. Modeling.

Two behavioral goals are achieved simultaneously during forward trunk bending in humans: the bending movement per se and equilibrium maintenance. The objective of the present study was to understand how the two goals are achieved by using a biomechanical model of this task. Since keeping the center of pressure inside the support area is a crucial condition for equilibrium maintenance during the movement, we decided to model an extreme case, called "optimal bending", in which the movement is performed without any center of pressure displacement at all, as if standing on an extremely narrow support. The "optimal bending" is used as a reference in the analysis of experimental data in a companion paper. The study is based on a three-joint (ankle, knee, and hip) model of the human body and is performed in terms of "eigenmovements", i.e., the movements along eigenvectors of the motion equation. They are termed "ankle", "hip", and "knee" eigenmovements according to the dominant joint that provides the largest contribution to the corresponding eigenmovement. The advantage of the eigenmovement approach is the presentation of the coupled system of dynamic equations in the form of three independent motion equations. Each of these equations is equivalent to the motion equation for an inverted pendulum. Optimal bending is constructed as a superposition of two (hip and ankle) eigenmovements. The hip eigenmovement contributes the most to the movement kinematics, whereas the contributions of both eigenmovements into the movement dynamics are comparable. The ankle eigenmovement moves the center of gravity forward and compensates for the backward center of gravity shift that is provoked by trunk bending as a result of dynamic interactions between body segments. An important characteristic of the optimal bending is the timing of the onset of each eigenmovement: the ankle eigenmovement onset precedes that of the hip eigenmovement. Without an earlier onset of the ankle eigenmovement, forward bending on the extremely narrow support results in falling backward. This modeling approach suggests that during trunk bending, two motion units--the hip and ankle eigenmovements--are responsible for the movement and for equilibrium maintenance, respectively.

Biomechanical Phenomena↗

PubMed2001

Biomechanical analysis of movement strategies in human forward trunk bending. II. Experimental study.

The large mass of the human upper trunk, its elevated position during erect stance, and the small area limited by the size of the feet, stress the importance of equilibrium control during trunk movements. The objective of the present study was to perform a biomechanical analysis of fast forward trunk movements in order to understand the coordination between movement and posture. The analysis is based on a comparison between experimentally observed bending and hypothetical "optimal bending" performed on an infinitely narrow support, as presented in a companion paper. The experimental data were obtained from 16 subjects who performed fast forward bending while standing on a wide platform or on a narrow beam. The analysis is performed by decomposition of the movement into three dynamically independent components, each representing a movement along one of the three eigenvectors of the motion equation. The eigenmovements are termed "hip", "ankle", and "knee" eigenmovements, according to the dominant joint. The experimentally observed movement is characterized mainly by the hip and ankle eigenmovements, whereas the knee eigenmovement is negligible. Similarly to the "optimal bending" the ankle eigenmovement starts earlier and lasts longer than the hip eigenmovement. An early forward acceleration of the center of gravity in the ankle eigenmovement is caused by anticipatory changes in the ankle joint torque. This clarifies the role of the early tibialis anterior burst and/or soleus inhibition usually observed in electromyographic recordings during forward bending. The results suggest that the hip and the ankle eigenmovements can be treated as independently controlled motion units aimed at functionally different behavioral goals: the bending per se and postural adjustment. It is proposed that the central nervous system has to control these motion units sequentially in order to perform the movement and maintain equilibrium. It is also suggested that the hip and ankle eigenmovements can be regarded as a biomechanical background for the hip and ankle strategies introduced by Horak and Nashner (1986) on the basis of electromyographic recordings and kinematic patterns in response to postural perturbations.

Adult↗

PubMed2000

Timed loaded standing: a measure of combined trunk and arm endurance suitable for people with vertebral osteoporosis.

Chronic back tiredness or fatigue is a common complaint of people who have a history of osteoporotic vertebral fracture. Trunk muscle endurance has not been studied in people with vertebral osteoporosis, partly due to the lack of assessment tools. We developed a measure of combined trunk and arm endurance suitable for people with vertebral osteoporosis, timed loaded standing (TLS). TLS measures the time a person can stand while holding a two-pound dumbbell in each hand with the arms at 90 degrees of shoulder flexion and the elbows extended. Intraclass correlation coefficients (ICCs) for same day inter-trial and six to ten day test-retest reliability were 0.89 (lower bound 95% confidence interval [LB 95% CI] 0.79) and 0.84 (LB 95% CI 0.68), respectively, in a sample of 21 older women with no known osteoporosis. In 127 women with vertebral fractures, the ICC for same day inter-trial reliability was 0.81 (LB 95% CI 0.75). In a sub-sample of 30 of these women with vertebral fractures, the six to ten day test-retest reliability was 0.85 (LB 95% CI 0.75). Moderately strong and statistically significant (p < or = 0.05) correlations were found between TLS and sixteen of eighteen measures of physical impairment and function. Functional reach distance, gait velocity, MOS-36 Physical Function Subscale, shoulder flexion strength, and six minute walk distance were most strongly associated with TLS time. Women with vertebral fractures who endorsed having back tiredness when standing and working with the arms in front of the body, sitting to rest because of back tiredness or pain, and planning rest periods because of back tiredness or pain had significantly lower TLS times. TLS is a simple, safe physical performance measure of combined trunk and arm endurance that demonstrates acceptable reliability (inter-trial and test- retest) and concurrent validity.

Aged↗

PubMed2006

Effects of neck muscles vibration on the perception of the head and trunk midline position.

The present study focused on the influence of neck vibration on the perception of the head and trunk midline position (orientation and localization). The orientation of the head and trunk was investigated by the rolling adjustment of a rod on their midline while their localization was investigated by the adjustment of the position of a visual dot as being straight-ahead the eyes or the sternum. The first experiment investigated whether a head-trunk dissociation was induced by the unilateral vibration of neck muscles in upright and restrained subjects. Results showed that the subjective orientation and localization of whole-body midline were shifted toward the vibrated side. The second experiment determined the effect of the neck muscles vibration when the subjects were lying on their side. The effect of vibration disappeared when the side of vibration was opposed to the side of postural inclination and it was stronger than in the upright position when the side of vibration and the side of postural inclination were congruent. Whereas, results suggested that the input from neck muscle proprioceptors participates directly to the elaboration of the egocentric space, the question may be raised as to how the sensory cues interacted in their contribution to the neural generation of an egocentric, body centred coordinate system.

Adult↗

PubMed2000

The effects of instability and additional hand support on anticipatory postural adjustments in leg, trunk, and arm muscles during standing.

We investigated the role of additional perceptual information (finger touch) and additional mechanical support (hand grasp) on the anticipatory postural adjustments (APAs) associated with fast arm movements performed by standing subjects. The subjects performed fast, unilateral shoulder ante-flexion movements while standing on a stable force platform or on an unstable board with instability in a sagittal or in a frontal plane. Changes in the background activity of leg, trunk, and arm muscles and displacements of the center of pressure were quantified within time intervals typical for APAs. Leg and trunk muscles showed a significant drop in APAs with added finger touch and no further changes when the touch was substituted with hand grasp. Arm muscles showed no changes or a small drop in APAs with touch and a significant increase in APAs with grasp. These changes were seen during both stable and unstable standing. We conclude that APAs can show changes associated not only with mechanical aspects of a task, but also with its perceptual aspects. Based on the equilibrium-point hypothesis of motor control, an additional analysis of APAs was performed. With additional support, we observed a significant modulation of an index related to the co-activation of agonist-antagonist muscle pairs, while no changes in reciprocal activation were found. A similar analysis performed across all the leg and trunk muscles with respect to control of the center of mass lead to similar results. We conclude that the central nervous system seems to simplify adjustments of control patterns to changes in task parameters by modulation of only one of the two major central commands.

Adult↗

PubMed2000

Morphometric study of the pulmonary trunk: implications for a new approach of the Ross procedure.

A pulmonary valve autograft may be proposed to replace diseased aortic valves. The explanted pulmonary valve is replaced with a pulmonary homograft with the inherent risk of calcified degeneration. A monocusp valve using the anterior pulmonary trunk has been proposed to reconstruct the right ventricular outflow tract. The aim of this study was to determine the feasibility of this technique. In hearts from 17 adult cadavers, we measured: pulmonary trunk diameter at the leaflet tops (D1). H1 and H2 were respectively from leaflet top to lower and upper levels of the pulmonary trunk bifurcation. D2 = 1.4 D1 was calculated as the monocusp size allowing a 45 degrees opening of the valve and thus permitting good valvular efficacy. G = H1 - D2 determined the feasibility of the technique: G greater than 10 mm, appeared the most favorable, G between 0 and 10 mm, appeared possible, and G less than 0, appeared to be impossible. Mean values of D1, H1 and H2 were respectively: 20.19 mm, 37 mm and 57 mm. The technique was possible in 16 cases (94%) and impossible in 1 case (6%). Preoperative determination of these parameters, by echocardiography or magnetic resonance imaging, appears necessary before applying this new surgical technique.

Adult↗

PubMed2002

Celiac trunk compression by arcuate ligament and living-related liver transplantation: a two-step strategy for flow-induced enlargement of donor hepatic artery.

The median arcuate ligament is a tendinous arch joining the two medial borders of the diaphragm crura together. In 10-50% of subjects it is responsible for significant angiographic celiac trunk compression. In severe cases, a decrease in hepatic arterial blood flow with subsequent artery caliber reduction and reverse vascularization via the gastroduodenal artery is present. In liver transplantation, small-caliber hepatic arteries are higher risk factors for hepatic arterial thrombosis and frequent graft loss. We report a case of celiac trunk compression in a living-related donor and the two-step strategy we developed to perform a safer liver transplantation via flow-induced enlargement of the donor hepatic artery. A 29-year-old father was selected as a living-related liver donor for his 4-year-old daughter. Angiography revealed celiac trunk compression by the median arcuate ligament with reverse vascularization of the middle hepatic artery via the gastroduodenal artery, a proper hepatic artery 2 mm in diameter irrigating the left lateral segment exclusively, and a right hepatic artery irrigating the right lobe and segment 4. First-step division of the median arcuate ligament and gastroduodenal artery ligation were performed. Repeat angiography at the third week showed a 50% enlargement of the middle hepatic artery (3 mm). Second-step left lobectomy was performed at the fifth week. The transplantation was achieved with an arterial anastomosis between the middle hepatic arteries of donor and recipient. This two-step strategy including median arcuate ligament division provided flow-induced enlargement of the donor middle hepatic artery for a safer transplantation with arteries of more suitable calibers.

Adult↗

PubMed2006

Multiple variations of the hepatobiliary vasculature including double cystic arteries, accessory left hepatic artery and hepatosplenic trunk: a case report.

Anatomical variations in the origins and branching patterns of the hepatobiliary arterial system may be encountered during both conventional surgical and laparoscopic cholecystectomy. We report a rare case of double cystic arteries arising from both the right hepatic artery and the proximal part of the posterior superior pancreaticoduodenal artery. Additional variations consisting of an accessory left hepatic artery arising from a left gastric which in turn arose from the descending aorta superior to the origin of the celiac trunk and a small left hepatic artery arising from the hepatic proper artery were also noted. The celiac trunk bifurcated into the splenic artery and the common hepatic artery forming a hepatosplenic or lienohepatic trunk. The possible clinical implications are discussed.

Cadaver↗

PubMed2000

Glue embolization of a ruptured celiac trunk pseudoaneurysm via the gastroduodenal artery.

Percutaneous transcatheter embolization of splanchnic artery aneurysms is a minimally invasive and alternative therapy to conventional surgical intervention. Due to a high-grade stenosis at the origin of the celiac trunk, a retrograde approach to the celiac trunk pseudoaneurysm via the gastroduodenal artery was necessary. To prevent undesirable embolization into the peripheral left gastric artery initial occlusion of the central portion of the left gastric artery was performed with microcoils using a Tracker catheter. Complete occlusion of the celiac trunk itself and the short adjacent segments of the celiac artery was achieved by using a mixture of N-butyl-2-cyanoacrylate and ethiodized oil as the embolizing agent.

Aneurysm, False↗

PubMed2000

Auditory role of lateral trunk channels in cobitid fishes.

In cobitid fishes the anterior part of the swimbladder is encapsulated by bone to varying extent. This might diminish the auditory sensitivity of these otophysine fishes by reducing the vibrations of the swimbladder wall in the sound field. However, according to prior studies the auditory thresholds of the cobitid Botia modesta is similar to that of other otophysine fishes. According to anatomical investigation B. modesta has a cranial encapsulation of the anterior part of the swimbladder (camera aerea Weberiana) as expected and in addition special channels stretching laterally from the swimbladder to the outer body wall. These lateral trunk channels are filled with fat and lymph. They form a muscle-free acoustic window beneath the skin, which could be demonstrated by measuring the auditory brainstem response at 400 Hz, 800 Hz, 1500 Hz, and 3000 Hz. Filling the lateral trunk channels with wettex (cotton/rayon staple) resulted in an increase of the auditory thresholds by 13.6-17.6 dB, indicating mechanical damping of the swimbladder. Our experiments demonstrate that the intact lateral trunk channels enhance the hearing sensitivity of cobitid fishes.

Air Sacs↗

PubMed2004

The role of back muscle endurance, maximum force, balance and trunk rotation control regarding lifting capacity.

Evaluation of lifting capacity is widely used as a reliable instrument in order to evaluate maximal and safe lifting capacity. This is of importance in regard to planning rehabilitation programs and determining working ability. The aim of this study was to investigate the influence of basic functions on the lifting capacity measured by the progressive isoinertial lifting evaluation (PILE) and the functional capacity evaluation (FCE) tests in a lower (floor to waist) and an upper (waist to shoulder) setting and compare the two test constructs. Seventy-four female subjects without acute low back pain underwent an examination of their lifting capacities and the following basic functions: (1) strength and endurance of trunk muscles, (2) cardiovascular endurance, (3) trunk mobility and (4) coordination ability. A linear regression model was used to predict lifting capacity by means of the above-mentioned basic functions, where the F statistics of the variables had to be significant at the 0.05 level to remain in the model. Maximal force in flexion showed significant influence on the lifting capacity in both the PILE and the FCE in the lower, as well as in the upper, lifting task. Furthermore, there was a significant influence of cardiovascular endurance on the lower PILE and also of endurance in trunk flexion on the lower FCE. Additional inclusion of individual factors (age, height, weight, body mass index) into the regression model showed a highly significant association between body height and all lifting tasks. The r (2) of the original model used was 0.19/0.18 in the lower/upper FCE and 0.35/0.26 in the lower/upper PILE. The model r (2) increased after inclusion of these individual factors to between 0.3 and 0.4. The fact that only a limited part of the variance in the lifting capacities can be explained by the basic functions analyzed in this study confirms the assumption that factors not related to the basic functions studied, such as lifting technique and motor control, may have a strong influence on lifting capacity. These results give evidence to suggest the inclusion of an evaluation of lifting capacity in clinical practice. Furthermore, they raise questions about the predictive value of strength and endurance tests in regard to lifting capacity and work ability.

Back↗

PubMed2000

Trunk muscle strength in eccentric and concentric lateral flexion.

The aim of this study was to investigate the position and velocity dependency of the strength (torque) output of lateral flexor muscles of the trunk. Twelve male volunteers with no history of back pain participated. Movement was constrained to the frontal plane and the velocity was controlled by an isokinetic dynamometer. The eccentric and concentric strength of lateral flexor muscles on the left side was measured in a supine position at velocities of 15, 30, 45 and 60 degrees x s(-1) and static strength at 20, 10, 0, -10 and -20 degrees of lateral trunk flexion. Average peak torque values ranged between 211 and 218 Nm (eccentric) and between 66 and 140 Nm (concentric) over all tested velocities, and the average static torque ranged between 80 and 172 Nm over all tested positions. The shape of the torque position curves was unaffected by speed and peak torque occurred at an average position of 11-15 degrees to the contralateral (right) side in both eccentric and concentric actions. In eccentric actions, torque output was significantly higher than that during concentric and static actions. Increasing the speed of contraction did not affect eccentric torque values, whereas both peak and angle-specific concentric torque decreased with increasing speed. These results are in general accordance with earlier findings from other muscle groups, such as the knee extensors. However, they are partially at variance with results obtained in studies of lateral lifting and lowering, indicating that there are other limiting factors in complex tasks that do not just involve the trunk muscles.

Adult↗

PubMed2004

Identification of the head-neck complex in response to trunk horizontal vibration.

A method is proposed for identifying the head-neck complex (HNC) in the seated human body when it is exposed to the trunk horizontal (fore-and-aft) vibration. It is assumed that the HNC only has the anteroposterior (flexion/extension) motion in the sagittal plane. An electrohydraulic vibrator is used as a source of vibration. To generate the trunk horizontal vibration, the trunk of the seated subject is fixed to the seatback. The subjects are exposed to the random vibration at a magnitude of 1.60 ms(-2) rms (root-mean-square) for 50 s. The coherence and frequency response function are then obtained in the frequency range 0.5-3 Hz. The results show that the HNC behavior is quasilinear with a resonance frequency between 1 and 1.4 Hz. Accordingly, a two-dimensional single-inverted pendulum is considered as a model for the HNC. The frequency domain identification method is then used to estimate the unknown parameters, including the HNC viscoelastic and inertia parameters. The model is examined in a time domain using the random vibration. Good agreement is obtained between experimental and simulation results, indicating the reliability of the proposed method.

Acceleration↗