Vleeming

We developed a biomechanical model of load transfer by the sacroiliac joints in relation to posture. A description is given of two ways in which the transfer of lumbar load to the pelvis in a stooped posture can take place. One way concerns ligament and muscle forces that act on the sacrum, raising the tendency of the sacrum to flex in relation to the hip bones. The other refers to ligament and muscle forces acting on the iliac crests, raising the tendency of the sacrum to shift in caudal direction in relation to the hip bones...

This study deals primarily with the stability of the base of the spine. The sacroiliac joints are vulnerable to shear loading on account of their predominantly flat surfaces. This raises the question of what mechanisms are brought into action to prevent dislocation of the sacroiliac joints when they are loaded by the weight of the upper part of the body and by trunk muscle forces. First a model is introduced to compare load transfer in joints with spherical and with flat joint surfaces. Next we consider a biomechanical model for the equilibrium of the sacrum under load, describing a self-bracing effect that protects the sacroiliac joints against shear according to 'the sacroiliac joint compression theory', which has been demonstrated in vitro...

Movement in eight sacroiliac joints was measured in preparations of embalmed elderly humans and compared with radiological findings. For the biomechanical part of the study the connections between sacrum and fifth lumbar vertebra were spared, as were the surrounding ligaments. The pelvis-spine preparation was fixed at the fifth lumbar vertebra. To induce movement, forces were directed at the acetabula. With digital displacement meters rotation was measured between the sacral and iliac part of the sacroiliac joint...

BACKGROUND: Back extension exercises are often used in the rehabilitation of low back pain. However, at present it is not clear how the posterior muscles are recruited during different types of extension exercises. Therefore, the present study will evaluate the myoelectric activity of thoracic, lumbar and hip extensor muscles during different extension exercises in healthy persons. Based on these physiological observations we will make recommendations regarding the use of extensions exercises in clinical practice...

STUDY DESIGN: Cohort study. OBJECTIVE: To construct a sagittal standing alignment classification system in which the clinical significance of identified subgroups was considered with spinal pain measures. SUMMARY OF BACKGROUND DATA: Numerous grading systems for the categorization of sagittal standing alignment have been devised. However, no common consensus exists about which typology should be adopted. Furthermore, the clinical significance of proposed classification schemes has rarely been assessed in terms of their relationship with spinal pain...

This article focuses on the (functional) anatomy and biomechanics of the pelvic girdle and specifically the sacroiliac joints (SIJs). The SIJs are essential for effective load transfer between the spine and legs. The sacrum, pelvis and spine, and the connections to the arms, legs and head, are functionally interrelated through muscular, fascial and ligamentous interconnections. A historical overview is presented on pelvic and especially SIJ research, followed by a general functional anatomical overview of the pelvis...

INTRODUCTION: From a clinical point of view, knowledge of customary standing positions among healthy young adolescents is of primary importance. The purpose of this study was to document the correlations between sagittal standing posture parameters in a pre-peak height velocity (pre-PHV) cohort. MATERIALS AND METHODS: This cohort study included 639 pre-PHV boys (age 12.6 [SD, 0.54] years) and 557 pre-PHV girls (age 10.6 [SD, 0.47] years). Gross body segment orientations and spinopelvic orientation/shape indexes were quantified using a clinical screening protocol...

In this overview, new and existent material on the organization and composition of the thoracolumbar fascia (TLF) will be evaluated in respect to its anatomy, innervation biomechanics and clinical relevance. The integration of the passive connective tissues of the TLF and active muscular structures surrounding this structure are discussed, and the relevance of their mutual interactions in relation to low back and pelvic pain reviewed. The TLF is a girdling structure consisting of several aponeurotic and fascial layers that separates the paraspinal muscles from the muscles of the posterior abdominal wall...

Movement and stability of the lumbosacral region is contingent on the balance of forces distributed through the myofascial planes associated with the thoracolumbar fascia (TLF). This structure is located at the common intersection of several extremity muscles (e.g. latissimus dorsi and gluteus maximus), as well as hypaxial (e.g. ventral trunk muscles) and epaxial (paraspinal) muscles. The mechanical properties of the fascial constituents establish the parameters guiding the dynamic interaction of muscle groups that stabilize the lumbosacral spine...

This study examined a potential cellular basis for strain hardening of fascial tissues: an increase in stiffness induced by stretch and subsequent rest. Mice lumbodorsal fascia were isometrically stretched for 15 min followed by 30 min rest (n=16). An increase in stiffness was observed in the majority of samples, including the nonviable control samples. Investigations with porcine lumbar fascia explored hydration changes as an explanation (n=24). Subject to similar loading procedures, tissues showed decreases in fluid content immediately post-stretch and increases during rest phases...

Summary. Sacroiliac joint dysfunction is often overlooked as a possible cause of low back pain. This is due to the use of reductionistic anatomical models. From a kinematic point of view, topographic anatomical models are generally inadequate since they categorize pelvis, lower vertebral column and legs as distinct entities. This functional-anatomical study focuses on the question whether anatomical connections between the biceps femoris muscle and the sacrotuberous ligament are kinematically useful. Forces applied to the tendon of the biceps femoris muscle, simulating biceps femoris muscle force, were shown to influence sacrotuberous ligament tension...

The objective of this study was to determine whether arachidonate metabolites are involved in the vasoconstrictive effects of angiotensin II in rats. In the isolated perfused heart, dexamethasone (4 mg/kg) significantly suppressed the maximal decreases in coronary flow induced by angiotensin II and vasopressin (reference drug). In the heart, the nonselective lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA, 1 muM) markedly suppressed the angiotensin II-induced decreases in coronary flow. NDGA (10 muM) inhibited both angiotensin II- and methoxamine- (reference drug) induced contractions in aortic rings with (in the presence of L-NAME) and without endothelium...

STUDY DESIGN: This cohort study compares motion characteristics during forward bending of a group of chronic female patients either with low back pain (LBP) or pelvic girdle pain (PGP) and healthy subjects using computer-video analysis. OBJECTIVE: This study determines whether subcategories of back pain patients could be distinguished by motion characteristics of the pelvis and lumbar spine. SUMMARY OF BACKGROUND DATA: Compared with healthy subjects, patients with low back pain bend forward in distinct manners...

STUDY DESIGN: Descriptive cohort study. OBJECTIVE: This study aims to further elucidate the differences in physical characteristics of women with severe pregnancy-related pelvic girdle pain (PGP). SUMMARY OF BACKGROUND DATA: There is increasing interest in pelvic girdle pain (PGP). To our knowledge, this is the first study on a large population of patients with severe PGP, after pregnancy, based on high cutoff scores on diagnostic PGP tests...

A guideline on pelvic girdle pain (PGP) was developed by "Working Group 4" within the framework of the COST ACTION B13 "Low back pain: guidelines for its management", issued by the European Commission, Research Directorate-General, Department of Policy, Coordination and Strategy. To ensure an evidence-based approach, three subgroups were formed to explore: (a) basic information, (b) diagnostics and epidemiology, and (c) therapeutical interventions. The progress of the subgroups was discussed at each meeting and the final report is based on group consensus...

We investigated whether inhaling peak concentrations of aldehydes several times daily is more damaging than semi-continuously inhaling low-dose aldehydes. We exposed Xpa-/-p53+/- knock-out mice either intermittently or semi-continuously to mixed acetaldehyde, formaldehyde, and acrolein. The intermittent regimen entailed exposure to the aldehydes 7 min every 45 min, 12 times/day, 5 days/week, corresponding to concentrations inhaled by smokers. Semi-continuously exposed animals received half the dose of aldehydes in 8h/day, 5 days/week...

STUDY DESIGN: A cross-sectional study in pregnancy. OBJECTIVES: To differentiate between pregnancy related pelvic girdle pain (PGP) and low back pain (LBP) in Iranian women, and investigate the prevalence of each syndrome. SUMMARY OF BACKGROUND DATA: Most of the information about PGP and LBP has been obtained in Western countries. There are few studies to investigate pregnancy related lumbopelvic pain, and, especially, differentiate between PGP and LBP in non-Western countries, particularly in the Middle East...

Stabilization exercises are intended to optimize function of the muscles that are believed to govern trunk stability. Debate exists whether certain muscles are more important than others in optimally performing these exercises. Thirty healthy volunteers were asked to perform three frequently prescribed stabilization exercises in four-point kneeling. The electromyographic activity of different trunk and hip muscles was evaluated. Average amplitudes obtained during the exercises were normalized to the amplitude in maximal voluntary contraction (% MVIC)...

Whole-body PET-scan studies in brains of tobacco smokers have shown a decrease in monoamine oxidase (MAO) activity, which reverts to control level when they quit smoking. The observed decrease in MAO activity in smokers is presumably due to their exposure to tobacco constituents that possess MAO-inhibiting properties. The inhibition of MAO activity seems, however, not to be a unique feature of tobacco smoking as subjects with Type II alcoholism have been reported to show a similar decrease in MAO activity that reverses when they cease to use alcohol...

In the present article a replication of a study by Fenigstein, Scheier and Buss (1975), who constructed a Self-Consciousness Scale (SCS), is reported. The SCS was translated into Dutch, and its properties and its relation to Locus of Control was investigated. The norms and reliability coefficients presented are consistent with prior research. Also the results of a factor analysis that yielded the three factors: Private, Public Self-consciousness, and Social Anxiety are consistent with these findings. However, Private Self-consciousness did not correlate significantly with Locus of Control...