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PubMed2002

A survey for nymphs of host-seeking Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) on tree trunks in deciduous forests.

Trunks of 83 trees in a mixed deciduous forests in Maryland were sampled for the presence of nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). Although one or more nymphs of either I. scapularis or A. americanum was found in leaf litter and substrate < or = 1 m from the bases of 47% of the trees sampled, a total of 6 I. scapularis nymphs was found on the trunks of only five trees. No nymphs were found on the trunks of 12 dead trees. No A. americanium nymphs were found on any tree trunks. The trunks were sampled to 2.5 m above the soil, but the nymphs were found < or = 1 m from the ground. More than 50% of I. scapularis nymphs found in the leaf litter < or = 1 m from bases of living trees were north of the trees sampled, whereas few I. scapularis were found west of trees. These findings suggest that the I. scapularis nymphs' presence on tree trunks is of little ecological consequence, unless nymphs were being removed from tree trunks by acquiring hosts at such a rapid rate that nymphal numbers on trunks could not accrue.

Animals↗

PubMed1997

Obliteration of the lymphatic trunks draining diaphragmatic lymph causes peritoneal fluid to enter the pleural cavity.

Pathways of peritoneal fluids to the pleural cavity in the rat were investigated by light microscopy and transmission electron microscopy (TEM). Intraperitoneally injected India ink was demonstrated to enter the subperitoneal lymphatics through lymphatic stomata, and to drain through the subpleural collecting lymphatics, into the parasternal, paravertebral and mediastinal lymphatic trunks as well as the thoracic duct. Five to 10 min after the intraperitoneal injection of India ink, the parasternal lymphatic trunk was ligated at the third intercostal space. Thirty minutes, 1 h, or 2 h after the ligation of either the right or the left trunk, India ink was macroscopically recognized only around the ligated trunk. When the right and left trunks were simultaneously ligated, India ink leaked around both trunks. Five hours after the ligation of both trunks, a massive amount of ink was located in the interstitium of the anterior thoracic wall. TEM revealed carbon particles passing through gaps of the lymphatic endothelial cells into the interstitial space, and partly reaching the mesothelial surface lining the anterior thoracic wall. Results show that obstruction or narrowing of the lymphatic trunks draining the diaphragmatic lymph causes a hydrothorax, indicating that this is at least one mechanism causing this during continuous ambulatory peritoneal dialysis and diseases with ascites.

Animals↗

PubMed2004

Effects of specific exercise instructions on abdominal muscle activity during trunk curl exercises.

STUDY DESIGN: A repeated-measures, counterbalanced design. OBJECTIVES: To test whether subjects could learn and retain the ability to alter the relative activity of abdominal muscle groups when performing trunk curl exercises. BACKGROUND: Although trunk curl exercises are widely prescribed, a disadvantage of trunk curls is that they primarily activate rectus abdominis, while the internal and external oblique abdominis muscles are considered to be more important contributors to lumbar stability. METHODS AND MEASURES: A convenience sample of 25 subjects performed trunk curl exercises in accordance with 3 different sets of instructions: nonspecific instructions (NS), instructions intended to emphasize rectus abdominis activity (RE), and instructions intended to emphasize oblique abdominis activity (OE). Electromyographic (EMG) activity was recorded from the upper and lower rectus and the internal and external oblique abdominis muscles while a physical target was used to insure that the trunk was raised to the same height for all conditions. Normalized root-mean-square EMG amplitude measures were used to test for instruction-dependent changes in the relative EMG activity of the rectus and oblique muscle groups. RESULTS: Following a single, brief, instruction session, subjects performing trunk curls had significantly greater normalized oblique:rectus EMG ratios when following OE instructions (mean [+/- SD] oblique-rectus ratio, 1.45 +/- 0.34) than when following RE (mean [+/- SD] oblique-rectus ratio, 0.76 +/- 0.24) or NS (mean [ISD] oblique-rectus ratio, 0.63 +/- 0.23) instructions. Retesting 1 week later indicated that subjects retained this skill. CONCLUSIONS: With minimal instruction, subjects are able to volitionally alter the relative activity of the oblique and rectus abdominis muscles when performing trunk curls. Incorporating instructions emphasizing oblique abdominis activity into lumbar stabilization programs appears promising and has potential advantages over other approaches to altering abdominal muscle activity during trunk

Abdominal Muscles↗

PubMed2002

Anatomical location of T2-3 sympathetic trunk and Kuntz nerve determined by transthoracic endoscopy.

OBJECT: Bilateral subaxillary transthoracic endoscopic sympathectomy (TES) is a popular procedure of upper thoracic sympathectomy. The anatomical locations of the T-2 and T-3 sympathetic trunks, as viewed under the endoscope, are varied in the rib head areas. In this study, the authors investigated the more visible anatomical locations of the T-2 and T-3 sympathetic trunks, the so-called nerves of Kuntz, and intercostal rami by performing transthoracic endoscopy. METHODS: Seventy patients with palmar hyperhidrosis undergoing bilateral TES (140 sides) via the anterior subaxillary approach were included in this study. The operative findings and video images of the T-2 and T-3 sympathetic trunks and ganglia were recorded and analyzed. The anatomical locations of the T-2 and T-3 sympathetic trunks along the horizontal axes of the rib heads were determined using a three-region system constructed by the authors. The area between the rib neck and the medial border of the rib head was equally divided into Region E (external half) and Region M (medial half). The area between the medial border of the rib head and the paravertebral ligament was defined as Region I. The incidence of the T-2 and T-3 sympathetic trunks found in Regions E, M, and I were 31.4 to 42.9%, 50 to 57.1%, and 7.1 to 11.4%, respectively, on the left side, and 24.3 to 34.3%, 57.1 to 65.7%, and 8.6 to 10%, respectively, on the right side. One right (1.4%) and six left (8.6%) Kuntz nerves originating from the T-3 sympathetic trunk were found in seven patients (10%). The intercostal ramus was found around the T-2 rib neck in 24 patients (34.3%), with 18 cases (25.7%) for each side. The intercostal ramus around the T-3 rib neck was found in 17 patients (24.3%): 12 (17.1%) on the right and nine (12.9%) on the left. CONCLUSIONS: These results indicate that approximately 90% of the T-2 or T-3 sympathetic trunks are located on the rib head. These findings may also be used to assist the surgeon in fluoroscopic guidance for locating the T-2 and T-3 sympathetic trunks during posterior percutaneous sympathectomy.

Adolescent↗

PubMedDate not supplied

Electromyographic activity of selected trunk muscles during stabilization exercises using a gym ball.

Trunk stabilization is very important for the injured lower back. The use of a gym ball, the surface of which is labile, is becoming more popular for strengthening the trunk muscles and challenging the motor control system in trunk stabilization exercises. However, little is known about the activity of the trunk muscles during such exercises. The purpose of this study was to compare the electromyographic (EMG) activity of the trunk muscles during seven stabilization exercises using a gym ball. Eleven healthy men (19.9 +/- 1.8 years old) without low back pain volunteered to participate in the study. Bipolar surface electrodes were attached to the right side of the upper and lower rectus abdominis, the obliquus externus abdominis and the upper and lower back extensor muscles. EMG signals were recorded during seven types of stabilization exercises using a gym ball and normalized to maximal voluntary contraction (% MVC). A two-way analysis of variance (ANOVA) was performed on % MVC from each task for each of the five trunk muscle sites (p < 0.05). Push-up exercise, supporting with both hands on the gym ball and toes on the floor in prone position, resulted in the highest activity of all abdominal muscles, and an exercise of the lifting the gym ball up, holding it actively between both legs with both knees flexed in supine position resulted in the lowest. Lifting up of the pelvis in a bridged position exercise, supporting the head with the gym ball and with the feet on the floor in supine position, resulted in higher muscle activity of the back extensor muscles than another exercise. It is very important for physical therapists to make clear the purpose of the trunk stabilization exercises, because different kinds of exercises with the gym ball demand various levels of muscular activity and use of various parts of the trunk muscles.

Adolescent↗

PubMed2005

Topographic study of root trunk type on Chinese molars with Class III furcation involvements: molar type and furcation site.

This study investigated the relationship between root trunk length and prognosis for molars with furcation involvement. Molars with furcation involvement were obtained from 169 patients affected with periodontitis. The test group consisted of 174 hopeless molars screened from a total of 441 molars with Class III involvement; the remaining 267 molars formed the control group. Both arches showed a significantly higher missing rate for teeth with a long root trunk length (type C) in second molars (41.3% and 32.4% in the maxilla and mandible, respectively), with a high degree of Class III furcation involvement for the test group (extracted hopeless or poor prognosis), compared to first molars (9.9% and 0.9% in the maxilla and mandible, respectively). Both arches had a significantly higher prevalence of long root trunk lengths in the second molars compared to first molars, irrespective of furcation site. Although first molars had an early and higher prevalence of Class III furcation involvement than second molars, the latter reached a significantly higher missing rate. Molars with longer root trunk lengths had a higher risk for poor prognosis than shorter root trunks when teeth were affected by Class III furcation involvement. For extracted furcation-involved maxillary second molars that failed to respond to periodontal therapy, long root trunk length (C) accounted for the greatest prevalence at the mesial furcation site (41.8%), followed by the distal (33.0%) and buccal sites (25.2%); the greatest prevalence of root trunk length C was found at the lingual (47.9%) and buccal furcation sites (45.1%) of mandibular second molars. When a molar with root trunk type C has a Class III involvement, the prognosis is poor; for the disease to reach that level, greater amounts of attachment must be destroyed.

Adult↗

PubMed1998

Effect of Trunk Position on Anterior Tibial Displacement Measured by the KT-1000 in Uninjured Subjects.

OBJECTIVE: Clinicians may obtain false-negative Lachman tests for tibial displacement when the trunk position of the athlete varies as the anterior cruciate ligament injury is assessed on the field, on the sideline, and in the clinic. We examined the influence of supine, semireclined, and sitting trunk positions on arthrometric laxity measurements of the knee. DESIGN AND SETTING: Subjects in the 3 trunk-thigh test positions (15 degrees , 45 degrees , and 90 degrees of hip flexion) were passively supported and tested in a counterbalanced order. The right knee was maintained at 29.0 degrees +/- 3.1 degrees of flexion. A 133-N (30-1b) anterior force was applied to the right knee using a modified KT-1000 knee arthrometer equipped with a strain gauge that allowed for digital display of the displacement force. SUBJECTS: Ten males and 5 females without present knee injury or history of knee ligament repair to the right lower extremity. MEASUREMENTS: Three tibial displacement (mm) trials at each trunk position were averaged and used for analysis. RESULTS: A 1-factor (trunk-thigh position) repeated-measures analysis of variance revealed no significant difference in anterior tibial displacement values among the 3 trunk-thigh positions (P > .05). Group means for displacement were 7.9 +/- 2.3 mm (supine), 8.1 +/- 2.5 mm (semireclined), and 8.3 +/- 2.6 mm (sitting). CONCLUSIONS: These findings suggest that alterations in trunk position are not a problem in the instrumented assessment of anterior tibial displacement in an uninjured population. Further research should determine the relevance of these findings, as well as "end-feel" (ie, stiffness) in subjects with injury to the anterior cruciate ligament. Further research should also determine if these findings can be applied when comparing passive versus active (eg, propped on elbows or hands) trunk support in subjects with anterior cruciate ligament-injured knees.

Journal Article↗

PubMed1991

[Anatomical study on the branches of the celiac trunk (IV). Comparison of the findings with Adachi's classification].

The authors studied the mode of branching of the celiac trunk in 184 Japanese cadavers during dissecting practice at Gifu University from 1985 to 1988. The findings were as follows; 1) One hundred and sixty-six of the 184 cases belonged to Type I of Adachi's classification of variation in the arrangement of the branches of the celiac trunk. One hundred and twenty-nine cases belonged to Group 1, one case to Group 2, 10 cases to Group 3, 9 cases to Group 4, one case to Group 6, 2 cases to Group 7, 8 cases to Group 8 and 4 cases to Group 11. Two cases did not belong to any group. One of them had an anastomosis between the hepatic artery and the superior mesenteric artery. The other one had the middle colic artery arising from the hepatic artery. 2) Seven cases belonged to Type II, Group 12. 3) Two cases belonged to Type III. One belonged to Group 18. The other one had an accessory right hepatic artery arising from the superior mesenteric artery. 4) One case belonged to Type IV, Group 20. 5) Three cases belonged to Type V, Group 23. 6) Two cases belonged to Type VI. One case had a gastrolienal trunk and an accessory right hepatic artery arising from the superior mesenteric artery. The other one had a gastrolienal trunk and an accessory right hepatic artery arising from the gastrolienal trunk. 7) Of the 184 cases, three could not be classified according to Adachi. Two cases had a gastrolienal trunk and the hepatic artery arising from the abdominal aorta. One case had a lienomesenteric trunk and a gastrohepatic trunk.

Aged↗

PubMed1990

Control of voluntary trunk movements in man. Mechanisms for postural equilibrium during standing.

The relatively large mass of the upper body and its elevated position in relation to the area of support during standing accentuate the importance of an accurate control of trunk movements for the maintenance of equilibrium. This fact has often been emphasized but never studied in detail. In this thesis the kinematics and motor patterns of simple voluntary trunk movements are investigated during standing. The analysis integrates neurophysiology and biomechanics using electromyographic (EMG) and optoelectronic techniques. Both the voluntary (primary movement) and the involuntary (associated postural adjustment) components of the movement are considered. The results demonstrate how the central nervous system (CNS) in its control of equilibrium utilizes biomechanical principles such as mechanical leverage of the different muscles and the interaction of active (muscle force) and passive forces (e.g. gravity and forces in stretched ligaments and/or muscles). Both primary and associated movements were found to be controlled by task specific and flexible muscle synergies which adapt to the mechanical demands of the situation. These task specific synergies were related to the amplitude, velocity and direction of the movement. Slow movements were often initiated through the action of gravity after a decrease or cessation of activity in postural muscles. Fast movements, however, were always initiated by a marked burst of activity in the agonist muscles. Significant relationships were observed between kinematical parameters (amplitude, duration and velocity) of fast trunk movements and temporal aspects of the EMG pattern. Multiple regression analysis indicated that the time to onset of muscle activity braking the ongoing trunk movement contained more information regarding the amplitude of the movement than did the duration of the initiating burst of activity in the prime mover. This supports the view that the initiating agonist burst is preprogrammed, whereas the braking antagonist burst may be influenced by peripheral feedback such as from muscle stretch receptors. In the early phase of a fast trunk flexion an unexpected flexion of the knees was observed. It is suggested that this knee flexion is a fast postural adjustment passively initiated as a mechanical consequence of the activation of muscles controlling the primary movement. This mechanism, which for anatomical reasons cannot act during an extension of the trunk, simplifies the feed-forward control of equilibrium during voluntary trunk flexion movements. For fast trunk extension movements a preactivation of ankle muscles occurred which resulted in a delay in the onset of the prime mover muscles when measured during a simple reaction time task.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗

PubMed1982

Trunk muscle strength and low back pain.

The strength of the trunk muscles was measured in a group of young males with low back insufficiency (n=7) and in an age matched (19-21 yrs) healthy control group (n=8). A recently designed new application of the isokinetic technique was used to record maximal torque produced by the trunk muscles during flexion, extension and lateral flexion. Trunk muscle strength was measured during isometric contractions in different trunk positions and during slow isokinetic contractions in the whole range of motion. No significant differences between the groups were observed for trunk extension, lateral flexion or flexion with the centre of rotation at L2-L3 level. However, in the initial part of isokinetic trunk flexion with the pivot point at the hip joint the strength values for the back patients were significantly lower than for the controls. The present results demonstrate the importance of a comprehensive approach to the assessment of trunk muscle strength, including different movement velocities, body positions and pivot points. Further studies are needed to evaluate the significance of the specific weakness observed in dynamic trunk flexion strength in the back patients.

Adult↗

PubMed1982

Trunk muscle strength during constant velocity movements.

A new apparatus has been designed for standardized measurements of the strength of human trunk muscles utilizing the isokinetic (constant movement velocity) technique (Cybex). It is possible to measure the produced torque during maximal voluntary isometric and isokinetic contractions in the whole range of motion during flexion, extension and lateral flexion of the trunk. Effects of gravity are eliminated since the movements are performed in the horizontal plane. Torque can be measured around different centres of rotation of the body. With this experimental set-up the strength of the trunk muscles has been characterized in a group of 14 normal male subjects (18-31 yrs). The torque produced by the trunk muscles varied with movement velocity and trunk position in the arc of motion. Peak torque occurred in a position where the muscles involved were stretched. The strength of the trunk extensors exceeded that of the flexors, but the degree (ratio) varied with trunk position. The relative contribution of the hip muscles to the total torque produced with the centre of rotation at the hip joint was larger for flexors than for extensors and varied with velocity and position. It is concluded that the present technique is useful to characterize the human trunk muscles.

Adolescent↗

PubMedDate not supplied

Locomotor head-trunk coordination strategies following space flight.

During locomotion, angular head movements act in a compensatory fashion to oppose the vertical trunk translation that occurs during each step in the gait cycle. This coordinated strategy between head and trunk motion serves to aid gaze stabilization and perhaps simplifies the sensory coordinate transformation between the head and trunk, allowing efficient descending motor control during locomotion. Following space flight, astronauts often experience oscillopsia during locomotion in addition to postural and gait instabilities, suggesting a possible breakdown in head-trunk coordination. The goal of the present investigation was to determine if exposure to the microgravity environment of space flight induces alteration in head-trunk coordination during locomotion. Astronaut subjects were asked to walk (6.4 km/h, 20 s trials) on a motorized treadmill while visually fixating on a centrally located earthfixed target positioned either 2 m (FAR) or 30 cm (NEAR) from the eyes. In addition, some trials were also performed during periodic visual occlusion. Head and trunk kinematics during locomotion were determined with the aid of a video-based motion analyzing system. We report data collected preflight (10 days prior to launch) and postflight (2 to 4 hours after landing). The coherence between pitch head and vertical trunk movements during gaze fixation of both FAR and NEAR targets was significantly reduced following space flight indicating decreased coordination between the head and trunk during postflight locomotion. Astronauts flying on their first mission showed greater alterations in the frequency spectra of pitch head movements as compared to their more experienced counterparts. These modifications in the efficacy of head movement control may account for the reported disruption in gaze performance during locomotion and may contribute to postflight postural and gait dysfunction.

Adult↗

PubMed1997

Human trunk extensor muscles physiology and ergonomics.

The paravertebral muscles (PM) act together with the hamstrings and calf muscles as important postural muscles. Both the histochemistry, biochemistry, strength and endurance of the PM were studied. Moreover attention was drawn to the exposure of PM, in particular the internal exposure level but to a certain degree repetitiveness and duration, in various job elements, and their various physiological acute responses. The thesis also deal with possible relations between the function of the PM and the magnitude of low-back trouble (LBP), and if PM muscle fatigue may play a role as a mediating factor for the occurrence of work related LBP. The lumbar PM is dominated by relatively small ST fibers with a well-developed network of capillaries, especially distinct in the central sections of PM (lumbar longissimus muscle) in females. It is remarkable that ST fibers are of the same size or larger compared to the FT fibers even in well-trained subjects. Further on PM is characterized by high activity levels of enzymes, oxidative as well as non-oxidative, important for the resynthesis of ATP and CrP. Also the level of muscles glycogen concentration is high. Altogether the PM have seemingly a potential for different metabolic pathways which may be selectively activated for a given activity. The average trunk extensor MVC varies in the different studies from 194-342 Nm and 252-450 Nm in females and males respectively. This is in accordance with predictions based specific strength, muscle cross sections and lever arms from the literature. The large range in strength due to dimension, age and training have to be considered when such data are used for e.g. ergonomic standardization and biomechanical modelling. The sex difference is smaller (female:male trunk extensor strength ratio = 0.7-0.8) than reported earlier. The small age reduction (25-60 year) of the trunk extensor strength, 0.5% per year, is probably caused by the fact that the ST dominated musculature is less sensitive to atrophy. The results indicate that a secular reduction of the trunk extensor strength has occurred during the last 2-3 decades possibly caused by a more sedentary lifestyle, both in working life due to mechanization introduced gradually during that period, and in leisure time activity. An important finding is that the static endurance time is significantly larger in the trunk extensors compared to other muscles, and larger in females than males. Possible explanations for the findings include 1) the reported histo- and biochemical results, 2) favorable blood flow conditions and 3) specific activation strategies of the muscles constituting the PM. In the vocational studies manifest signs of fatigue in the lumbar paravertebral muscles, are seen, including changes in both the energy spectra of the surface EMG towards lower frequencies and increases in the RMS amplitude, reduction of the static endurance time, and increase in the rate of perceived exertion during a working day in bricklayers performing highly repetitive work with their trunk extensors (1000:1200 bricks per day). Similar events do also occur during standing letter sorting with a very low close to static exposure of PM. Ergonomic arrangements may have a marked reducing effect on the internal exposure of PM especially if the job include manual handling operations (e.g. forest work, aircraft loading), but it is not possible to compensate for repetitiveness, and long task duration by so-called "good" ergonomics (e.g. introducing mats or shoes in upright working operations). The chronic effects (i.e.LBP) are also studied. It is found that trunk extensor static endurance time in 77 postmen was related to the degree of LPB, but this was not the case for strength of the trunk-extensors and flexors. Thus, it is shown that a broad variety of work related exposures may cause muscle fatigue in PM. The possible aetiological role of muscle fatigue is however not explained. (ABSTRACT TRUNCATED)

Adolescent↗

PubMed1999

Common brachiocephalic trunk: strategies for revascularization.

BACKGROUND: A common brachiocephalic trunk, in which both common carotid arteries and the right subclavian artery arise from a single trunk off the arch, is a normal variant of aortic arch branching that occurs in approximately 10% of the population. Because three of the four primary sources of cerebral blood flow arise from a single aortic branch, stenosis or occlusion of a common trunk can cause severe ischemic consequences. Common trunk revascularization has been described, but there have been no reports focusing on the management options for occlusive disease of this vascular anatomy. METHODS: A retrospective review of our experience with innominate artery revascularization identified 6 patients who underwent revascularization of a common brachiocephalic trunk between 1977 and 1997. All patients were symptomatic, with either total occlusion (n = 3) or critical stenosis (n = 3) caused by atherosclerosis (n = 5) or Takayasu's arteritis (n = 1). Revascularization was achieved by a prosthetic bypass graft from the ascending aorta to the innominate or left common carotid arteries or both (n = 5); or transarterial endarterectomy (n = 1). Concomitant endarterectomy of branch vessels was performed in 3 patients. RESULTS: There was one perioperative death from myocardial infarction, and one perioperative stroke, with death occurring 1 month after hospital discharge. One patient developed cerebral hyperperfusion syndrome 1 week after endarterectomy that resolved without sequelae with antihypertensive medications. During a follow-up period ranging from 1 to 20 years, there was one late death from congestive heart failure 5 years after operation. All surviving patients are alive and free from symptomatic recurrence. CONCLUSIONS: Revascularization for occlusive disease of a common brachiocephalic trunk can be achieved with effective and durable relief of symptoms using either a prosthetic bypass graft or endarterectomy. However, neurologic complications in 2 patients, which were fatal in 1, attest to the potential cerebral ischemic threat posed by occlusive disease of a common brachiocephalic trunk.

Adult↗

PubMed2003

The implications of common brachiocephalic trunk on associated congenital cardiovascular defects and their management.

A common brachiocephalic trunk is an anatomic variant in which both common carotid arteries and the right subclavian artery arise from the aortic arch via a single trunk. The impact of this condition on associated congenital cardiac malformations is presently unknown. Out of a total of 1480 cardiac catheterizations performed in children over a period of 10 years, we discovered 48 patients (3.2%) to have a common brachiocephalic trunk, of whom 98% had associated congenital cardiac malformations. A spectrum of associated lesions was identified, including left-to-right shunts in 19 patients, right-sided anomalies in 18 patients, left-sided obstructive lesions in 12 patients, and coronary arterial abnormalities in 10 patients, eight of whom had other cardiac defects. Genetic syndromes were present in one-fifth of the cases. When found with left-sided malformations, the common trunk was associated with persistent hypoplasia of the aortic arch, likely related to diminished flow through the arch during development. In each of four patients in whom the brachiocephalic trunk had been used during construction of a palliative shunt, we observed inadequate growth and deformation of the pulmonary arteries. Thus, angiographic identification of a common brachiocephalic trunk may be a marker for the presence of accompanying congenital cardiac defects and coronary arterial abnormalities. Understanding the pathophysiologic effects of the common trunk is important when planning the palliative or corrective procedures, and when assessing the potential benefit of the surgical repair over the long term.

Brachiocephalic Trunk↗

PubMed1989

Loads on the lumbar trunk during level walking.

The goal of this study was to estimate the loads internal to the lumbar trunk that arise during level walking. To do this, (a) trunk muscle activities were calibrated in terms of muscle contraction force levels in a set of isometric exertions; (b) trunk muscle myoelectric activities were measured during level walking; and then (c) the muscle contraction forces that arose during walking were calculated from these measurements and calibrations. Lumbar trunk muscle myoelectric activities were quantified in 10 healthy young males. Myoelectric activities were monitored using eight bipolar surface electrode pairs placed around the trunk at the level of the third lumbar vertebrae. The subjects first performed four static weight-resisting tasks to calibrate muscle force/activity relationships. They then traversed a 8.25 m walkway three times each at cadences of 72 and 120 steps/min. A biomechanical model incorporating 22 lumbar trunk muscles was used to predict muscle contraction forces for the calibration tasks. Predicted forces were linearly correlated with the measured myoelectric activities for these tasks. The regression equations were then interpolated to estimate the muscle contraction forces from the myoelectric data during gait. Peak contraction forces for the iliocostalis muscles were calculated to be approximately 55 N per side, corresponding to total erector spinae peak contractions on the order of 140 N per side. For the other six muscles that were monitored, contraction forces were less than 15 N per side. This suggests that peak net reaction moments and peak spine compressions on the lumbar trunk during these walking tasks were on the order of 15 Nm and 1.2 times body weight, respectively.

Abdominal Muscles↗

PubMed1993

Responses of intra-abdominal pressure and abdominal muscle activity during dynamic trunk loading in man.

The purpose of this study was to determine and compare interactions between the abdominal musculature and intra-abdominal pressure (IAP) during controlled dynamic and static trunk muscle loading. Myoelectric activity was recorded in six subjects from the rectus abdominis, obliquus externus, obliquus internus, transversus abdominis and erector spinae muscles using surface and intra-muscular fine-wire electrodes. The IAP was recorded intra-gastrically. Trunk flexions and extensions were performed lying on one side on a swivel table. An adjustable brake provided different friction loading conditions, while adding weights to an unbraked swivel table afforded various levels of inertial loading. During trunk extensions at all friction loads, IAP was elevated (1.8-7.2 kPa) with concomitant activity in transversus abdominis and obliquus internus muscles--little or no activity was seen from rectus abdominis and obliquus externus muscles. For inertia loading during trunk extension, IAP levels were somewhat lower (1.8-5.6 kPa) and displayed a second peak when abdominal muscle activity occurred in the course of decelerating the movement. For single trunk flexions with friction loading, IAP was higher than that seen in extension conditions and increased with added resistance. For inertial loading during trunk flexion, IAP showed two peaks, the larger first peak matched peak forward acceleration and general abdominal muscle activation, while the second corresponded to peak deceleration and was accompanied by activity in transversus abdominis and erector spinae muscles. It was apparent that different loading strategies produced markedly different patterns of response in both trunk musculature and intra-abdominal pressure.

Abdomen↗

PubMed1999

Anatomy of the common trunk of the middle and left hepatic veins: application to liver transplantation.

An anastomosis between the common trunk of the middle and left hepatic veins of the receiver and the cranial portion of the inferior vena cava of the donor is one of the techniques for restoration of hepato-caval continuity in orthotopic liver transplantation. This technique avoids dissection of the retrohepatic vena cava and total caval clamping. The aim of this study was to define the feasibility of this technique by a morphologic and biometric study of the common trunk of the middle and left hepatic veins on the basis of 64 injection-corrosion hepatic specimens and 21 fresh subjects. A common trunk for the middle and left hepatic veins was present in 54 of 64 cases (84%) with a length of 3 to 17 mm. The diameter of the new ostium constructed by section 0.5 cm proximal to the junction of the middle and left hepatic veins was 23.9 +/- 2.3 mm, which approximated to that of the vena cava where it traversed the diaphragm (24.4 +/- 2.0 mm). These findings confirmed that restoration of hepato-caval continuity by anastomosis between the common trunk of the middle and left hepatic veins of the receiver and the cranial portion of the vena cava of the graft is possible without incongruence. This study makes no assumptions about the hemodynamic effects associated with the smallest diameter of the true ostium of the common trunk at its opening into the inferior vena cava. In this study, the morphology of the common trunk was comparable to that observed by Nakamura. Further, we propose an anatomo-clinical classification allowing evaluation of the facility of vascular control of the common trunk in terms of the number and location of the collateral veins.

Cadaver↗