Posture related to myoelectric silence of erectores spinae during trunk flexion

Electromyographic activity of erectores spinae exhibits points of abrupt change during trunk flexion from the erect position and return extension. This study examined the positions at which the myoelectric activity suddenly disappeared and later reappeared. Forty adults were investigated to define accurately the inclinations of the trunk, pelvis, and vertebral column at these positions. The positions at the commencement and cessation of the period of electrical silence both occurred at two-thirds of maximum trunk flexion (mean = 80 degrees +/- 13 degrees SD). At these positions, all flexion measurements were significantly less than their maxima (P less than 0.001). Hip flexion at the commencement of electrical silence was slightly above one-half its maximum range, and similar to the position at the recommencement of electrical activity (mean = 40 degrees +/- 12 degrees SD). The most reproducible measurement (r = 0.88) in both positions was vertebral flexion (89% Max.; mean = 48 degrees +/- 6 degrees SD). Eleven of the male subjects repeated the experimental task holding 10.1 kg in their hands. The effect of this was to produce inhibition and reactivation of erectores spinae at a greater degree of vertebral flexion.     

Pressure in the erector spinae muscle during exercise

The microcapillary infusion method was evaluated in recording intramuscular pressure during isometric and concentric exercise of the erector spinae muscle. Intramuscular pressure at rest was 6.1 (SD = 1.4) mm Hg without infusion and 8.3 with an infusion rate of 1.5 ml/hour. When the subject experienced muscle fatigue during exercise, the muscle relaxation pressure had increased to 14 mm Hg. The erector spinae muscle was found to be heavily loaded during exercise with an average muscle contraction pressure of 175 mm Hg. Recording of intramuscular pressure in the erector spinae muscle during exercise tests can be an additional method in the study of ergonomics and biomechanics of the spine as well as in the diagnosis of chronic compartment syndrome in this muscle.     

Altered erector spinae activity and trunk motion occurs with moderate and severe unilateral hip OA

People with hip osteoarthritis (OA) demonstrate altered movement patterns in the hip joint, as well as the pelvis and spine. While kinematic changes have been described in the literature, little is known about the associated erector spinae (ES) activity. Increased or prolonged ES activity may contribute to the low back pain often associated with hip OA. Using a cross‐sectional cohort study, 3D trunk motions and ES surface electromyography were recorded on 19 individuals with severe OA (SOA), 20 with moderate hip OA (MOA), and 19 asymptomatic (ASYM) individuals during treadmill walking, using standardized collection and processing procedures. Principal component analysis was used to derive electromyographic amplitude and temporal waveform features. Three‐dimensional thoracic motion in a global system, and thoraco‐lumbar motion was calculated. Various statistical analyses determined between group differences (α = 0.05). In the sagittal plane, thoracic motion was greater in the SOA group (p < 0.001), whereas the ASYM group used less thoraco‐lumbar motion than either OA group (p ≤ 0.002). Greater frontal plane angular excursion during early stance was found in the thoracic region in the SOA group (p ≤ 0.001) . With increasing OA severity, bilateral ES activity increased during the swing phase of gait (p < 0.001), whereas during stance, the SOA ipsilateral ES activity was higher than other groups (p < 0.001). Statement of clinical significance: with moderate and severe OA, sagittal, and frontal trunk motion increases during gait. ES activity during the entire gait cycle is more sustained with increased disease severity, which may aide our understanding of low back pain associated with hip OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1826–1832, 2018.

     

The attachments of the lumbar erector spinae

The attachments and orientation of every fascicle of the lumbar erector spinae were determined in five cadavers and recorded radiographically. Little variation was found in the sites of muscle attachment, which enabled the construction of maps whereby these sites could be plotted on clinical radiographs or models of the lumbar spine. When all fascicles were plotted on 21 clinical radiographs using the maps previously developed, no significant difference in the orientation of fascicles was found compared with that observed in cadavers. This result vindicates the technique used to plot the location of individual fascicles of the lumbar back muscles.     

Coactivation of the hamstrings and quadriceps during extension of the knee

The electromyographic activities of six muscles of the thigh were recorded, using bipolar surface electrodes, during active extension of the knee by six healthy men. The signal amplitudes were normalized to those recorded during isometric maximum voluntary contractions. Extension of the knee from 90 to 0 degrees (full extension) was performed at the rate of 10 degrees per second with the leg unimpeded and with weights of 1.8, 3.6, 5.4, or 7.2 kilograms attached to the ankle. The hamstrings were found to coactivate with the quadriceps during the terminal phase of extension. Coactivation of all three hamstrings was found to occur at joint angles of as much as 9 degrees, with the maximum at full extension of the knee and the strength of the signals ranging to as much as 20 per cent. The signals of all of the flexors and extensors increased with increasing loads on the ankle and, with the exception of the rectus femoris at 9 degrees of flexion, they also increased as the knee extended. The results of this study support the hypothesis that the hamstrings function synergistically with the anterior cruciate ligament to prevent the anterior tibial displacement that is produced by active contraction of the quadriceps in the terminal degrees of extension of the knee. This information is important for the physical conditioning of healthy individuals in preparation for athletic endeavors. Furthermore, if coactivation of the hamstrings with the quadriceps is mediated by sensors other than, or in addition to, those of the anterior cruciate ligament, then strengthening of the hamstrings appears to be an important adjunct to rehabilitation programs after repair or reconstruction of that ligament.     

Posture-dependent isometric trunk extension and flexion strength in normal male and female subjects

The objective of this study was to quantify the relationship between trunk posture and trunk muscle function in a group of young, normal male and female subjects. Ten male and 10 female subjects performed isometric flexion and extension tasks using a trunk dynamometer. Peak isometric torque was recorded in flexion and extension at 10 degrees increments over a sagittal posture range of -20 degrees extension to +50 degrees of flexion. Significant differences in trunk strength (isometric torque) were found between males and females, at various sagittal plane trunk postures, and between flexion (F) and extension (E) tasks. Flexion torque was greatest at 20 degrees to 30 degrees flexion, whereas extension torque was greatest at 50 degrees flexion. Gender-specific differences in trunk strength were markedly reduced when the torque data were normalized by the subject's height multiplied by body weight. The E/F torque ratio showed a relatively linear, over twofold increase with increasing flexion angle, and was significantly greater for female subjects compared with male subjects at most sagittal postures. The baseline trunk isometric strength data provided by this study should help clinicians to use strength testing more precisely and specifically in prevention and diagnosis of patients at risk for back disorders.     

Isokinetic measurements of trunk extension and flexion performance collected with the biodex clinical data station

The purposes of the two experiments presently reported were to determine a) the relationship between subject-dynamometer axis alignment and isokinetic trunk extension-flexion performance and b) the effects of short-term acclimation to the isokinetic dynamometer on the magnitude of isokinetic trunk extension-flexion variables for low back pain and asymptomatic subjects. In the first study, three anatomic landmarks were selected for fixed axis alignment, the anterior superior iliac spine, the femoral greater trochanter, and the posterior superior iliac spine. Ten healthy women performed five reciprocal maximal effort, 100 degrees , concentric contraction trunk extension-flexion cycles at three isokinetic speeds (60, 120, 180 degrees /sec) for each of three subject-dynamometer configurations. Peak torque and the trunk angle at which peak torque occurred for both trunk extension and flexion were analyzed. A 3 x 3 analysis of variance did not provide definitive statistical evidence of the superiority of one alignment over the others. The data generated with the anterior superior iliac spine alignment, however, was more consistent than others relative to expected speed-torque relationships and was associated with the overall smallest variability of the data. In the second study, 8 healthy men and 10 men with a history of low back pain were studied with a within-session, test-retest protocol. The peak torque and total mechanical work for trunk flexion and trunk extension were analyzed. As a group, the low back pain subjects demonstrated universal and, in some cases, large performance improvement (>20%) at the retest. The results of the first study suggest that subject-dynamometer alignment using the anterior superior iliac spine is justifiable. Based upon the results of the second study it was concluded that a clinically relevant measure of sagittal plane isokinetic trunk flexion and extension function for low back pain patients should be collected using a test-retest protocol. J Orthop Sports Phys Ther 1990;11(12):590-598.     

Geometry of adult rectus abdominis and erector spinae muscles*

Mathematical modeling of human joints requires accurate information concerning anthropometric parameters such as muscle cross-sectional areas and muscle moment arms. The purpose of this study was to calculate the average crosssectional area, average volume, and length of the muscle moment arms about the spinal column for the rectus abdominis (RA) and the erector spinae (ES) for those portions of the muscles that are involved in spinal flexion and extension. Materials for this study came from archival computed tomography scans of 28 living subjects. The muscle outlines were digitized and the moment arms calculated as a percentage of anteroposterior trunk depth. The average cross-sectional area of the RA was 10.5 cm2, and 31.75 cm2 for the ES. The average volumes for the RA and ES were 356.16 cm3 and 843.46 cm3, respectively. The muscle moment arm ratio was 0.29 for the ES, while the males and females had ratios of 0.50 and 0.40, respectively, for the RA. Computed tomography scanning is a method that allows the accurate calculation of internal anthropometric parameters that will be of use in mathematical modeling. J Orthop Sports Phys Ther 1985;6(5):278-280.     

Motion of the femoral condyles in flexion and extension during a continuous lunge

Numerous studies have reported on in‐vivo posterior femoral condyle translations during various activities of the knee. However, no data has been reported on the knee motion during a continuous flexion‐extension cycle. Further, few studies have investigated the gender variations on the knee kinematics. This study quantitatively determined femoral condylar motion of 10 male and 10 female knees during a continuous weightbearing flexion‐extension cycle using two‐dimensional to three‐dimensional fluoroscopic tracking technique. The knees were CT‐scanned to create three‐dimensional models of the tibia and femur. Continuous images of each subject were taken using a single‐fluoroscopic imaging system. The knee kinematics were measured along the motion path using geometric center axis of the femur. The results indicated that statistical differences between the flexion and extension motions were only found in internal‐external tibial rotation and lateral femoral condylar motion at the middle range of flexion angles. At low flexion angles, male knees have greater external tibial rotation and more posteriorly positioned medial femoral condyle than females. The knee did not show a specific pivoting type of rotation with flexion. Axial rotation center varied from lateral to medial compartments of the knee. These data could provide useful information for understanding physiological motion of normal knees. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:591–597, 2015.     

A new robust index for measuring isokinetic trunk flexion and extension. Outcome from a regional study

The purpose of this study was 1) to provide normative data for isokinetic trunk strength as measured by peak torque, best work repetition, and a new composite variable, "muscle performance index"; and 2) to examine the effects of protocol velocity, subject age, gender, height, and weight on these measurements. A significant decrease in peak torque of extension for females (P less than 0.0001) was seen as protocol velocity increased, but no differences were seen in males. A statistically significant amount (0.5-0.7) of the variance in isokinetic measurements was explained by subject age, height, and weight. Multivariant analysis of covariance showed the effects of these variances to be significant on all measurements except for the muscle performance index, which was unaffected by protocol velocity and remained stable without adjustments for subject age, weight, or height.     

Histochemistry and morphology of erector spinae muscle in lumbar disc herniation

The purpose of this study was to detect any changes in the erector spinae muscles in patients undergoing surgery for lumbar disc herniation (LDH) and to analyze which factors (sex, age, the level and site of disc protrusion, and duration of symptoms) would be related to these changes. The percentage of mean area of the type I fibers was significantly larger in males and in the older age group (P less than 0.05), due to the decreasing size of type IIa and IIb fibers. Patients with LDH have: 1) angulated and selective atrophy of type II fibers with a higher type IIb/IIa ratio; 2) with increasing age and duration of symptoms, more marked atrophy of type II fibers; and 3) other unspecific pathologic changes.     

Effects of pelvic and lower extremity stabilization on isometric trunk extension and flexion muscle strength*

The purpose of this study was to evaluate the effect of varying the type of pelvic and lower extremity stabilization on isometric trunk extension and flexion muscle strength measurements. Two pelvic stabilization systems, one consisting of fixation of the anterior superior iliac spines and sacrum (pelvic fixation) and the second, a strap across the anterior superior iliac spines and a posterior pad at the sacrum (pelvic strap) were compared. The lower extremities were or were not strapped at the thigh, calf, and feet. Torque values for the pelvic fixation system were not different from the pelvic strap system with lower extremity stabilization. Torque values were less with no lower extremity stabilization with both pelvic stabilization systems for flexion but not for extension muscle contractions. The use of an extensive pelvic stabilization system did not produce greater isometric force output than the use of a simple pelvic strap. The use of lower extremity stabilization did produce greater isometric flexion force output than the use of no lower extremity stabilization. J Ortho Sports Phys Ther 1987;9(3):111-117.     

超声引导下竖脊肌平面阻滞临床应用及研究进展

超声引导下竖脊肌平面阻滞(erector spinae plane block,ESPB)是一项新颖的筋膜间隙阻滞技术,可以应用于胸腰部手术后镇痛,具有操作简单安全、镇痛可靠、并发症少等诸多优点。ESPB自2016年提出以来,得到广泛关注。文章介绍了超声引导下ESPB的解剖基础,阐述了ESPB起效的理论学说,归纳了ESPB在胸腹部及腰椎等手术的临床应用,总结了ESPB的优缺点及并发症,并将ESPB与胸腰部其他常用镇痛阻滞方法进行对比,分析了各自的特点。超声引导下ESPB具有诸多的优点、极少的并发症及禁忌证,在麻醉和疼痛领域存在广阔的应用空间,能提高麻醉效果和麻醉安全性。文章旨在探究ESPB的临床研究及未来发展方向,为其临床应用提供依据。     

Geometric measurements of the lumbar spine in Chinese men during trunk flexion

STUDY DESIGN: An analysis of the geometric data of the lumbar spine in Chinese men. Lateral radiographs were obtained of 16 men in the upright position to a trunk flexion of 90 degrees in 30 degrees increments. OBJECTIVES: To establish reference data concerning the geometry of the lumbar spine for various degrees of trunk flexion. SUMMARY OF BACKGROUND DATA: In previous studies, the morphometry and alignment of the lumbar spine have been investigated. Reports of systematic analyses of the lumbar spine in trunk flexion have lacked adequate radiographic data. Moreover, few studies have focused on measuring lumbar spine geometric data in Chinese individuals. METHODS: A total of 67 landmarks on each radiograph were identified. They were marked by investigators and digitized using a HyperSpace digitizing system (V.17: Mira Imaging Inc., Salt Lake City, UT). The geometric configuration of the vertebrae and discs then was derived from the digitized points. RESULTS: The dimensions of the vertebrae and disc on the lumbar spine obtained in this study were similar to those of previous studies. The motion of the lumbosacral spine had the greatest contribution in trunk flexion, approximately 90% (i.e., rotating at the rate of 9 degrees for each 10 degrees of trunk flexion) when the trunk was flexed from 30 degrees to 60 degrees. After that, the hips were dominant in accomplishing the trunk flexion from 60 degrees to horizontal. This motion patterns may be useful for making clinical diagnoses of lumbar function in Chinese men. CONCLUSIONS: No obvious interracial differences were found in the geometric data found in this study, which suggests that morphometric data obtained from Caucasian individuals may be applied to Chinese patients for clinical purposes.