vendex and Lordosis

A prospective study was performed on the assessment of both thoracic and lumbar spine sagittal profiles (from C7 to S1).. To propose a new noninvasive method for measuring the spine curvatures in standing and lying prone positions and to analyze their relationship with various biometric characteristics.. Modifications of spine curvatures (i.e. lordosis or kyphosis) are of importance in the development of spinal disorders. Studies have emphasized the development of new devices to measure the spine sagittal profiles using a noninvasive and low-cost method. To date, it has not been applied for analyzing both lumbar and thoracic alterations for various positioning.. Seventy-five healthy subjects (mean 22.6 ± 4.3 yr) were recruited to participate in this study. Thoracic and lumbar sagittal profiles were assessed in standing and lying prone positions using a 3D digitizer. In addition, several biometric data were collected including maximal trunk isometric strength for flexion and extension movement. Statistical analysis consisted in data comparisons of spine profiles and a multivariate analysis including biometric features, to classify individuals considering low within- and high between-variability.. Kyphosis and lordosis angles decreased significantly from standing to lying prone position by an average of 13.4° and 16.6°, respectively. Multivariate analysis showed a sample clustering of 3 homogenous subgroups. The first group displayed larger lordosis and flexibility, and had low data values for height, weight, and strength. The second group had lower values than the overall trend of the whole sample, whereas the third group had larger score values for the torques, height, weight, waist, body mass index, and kyphosis angle but a reduced flexibility.. The present results demonstrate a significant effect of the positioning on both thoracic and lumbar spine sagittal profiles and highlight the use of cluster analysis to categorize subgroups after biometric characteristics including curvature measurement.. N/A.

Topics: Adolescent; Adult; Biometry; Body Height; Body Mass Index; Body Weight; Female; Healthy Volunteers; Humans; Imaging, Three-Dimensional; Isometric Contraction; Kyphosis; Lordosis; Lumbar Vertebrae; Male; Muscle Strength; Muscle, Skeletal; Prone Position; Prospective Studies; Range of Motion, Articular; Thoracic Vertebrae; Torque; Torso; Young Adult

Lordosis is the bending of the lumbar spine that gives the vertebral column of humans its characteristic ventrally convex curvature. Infants develop lordosis around the time when they acquire bipedal locomotion. Even macaques develop a lordosis when they are trained to walk bipedally. The aim of this study was to investigate why humans and some animals develop a lumbar lordosis while learning to walk bipedally.. We developed a musculoskeletal model of the lumbar spine, that includes an asymmetric, dorsally shifted location of the spinal column in the body, realistic moment arms, and physiological cross-sectional areas (PCSA) of the muscles as well as realistic force-length and force-velocity relationships. The model was used to analyze the stability of an upright body posture. According to our results, lordosis reduces the local joint torques necessary for an equilibrium of the vertebral column during an erect posture. At the same time lordosis increases the demands on the global muscles to provide stability.. We conclude that the development of a spinal lordosis is a compromise between the stability requirements of an erect posture and the necessity of torque equilibria at each spinal segment.

Topics: Humans; Lordosis; Lumbar Vertebrae; Models, Biological; Posture; Torque

The current successful management of idiopathic scoliosis is an orthopaedic and not a paediatric responsibility. Hence the immediate aim of etiologic research is to improve surgical treatments based on a better understanding of the causation of the deformity. This focuses attention on the pathomechanisms of the spinal and ribcage deformities. The mechanisms of spinal deformity about the apex are unresolved but may be caused by forces created in the anterior spinal column. Some current theories with practical application involve (1) front-back spinal growth mechanisms, (2) rib growth asymmetry and (3) muscles.. The application of theory to surgical practice is advanced for concepts of front-back spinal growth asymmetry but rib hump reassertion occurs after surgery and these concepts ignore the ribcage as a possible factor in scoliosis pathogenesis. A theory of ribcage asymmetry involving concave rib overgrowth is beginning to be evaluated surgically. After surgery for IIS and AIS reassertion of the deformity has been shown to involve preoperative spinal and concave rib factors; the larger the concave rib-spinal angle the better results at 2-5 year. Muscular factors that may trigger/exacerbate the apical spinal deformity of scoliosis need more research. The concept that AIS pathogenesis involves putative neuromuscular dysfunction that deforms an immature spine is considered likely by several workers.

Topics: Adolescent; Biomechanical Phenomena; Bone Remodeling; Child; Functional Laterality; Humans; Isometric Contraction; Lordosis; Lumbar Vertebrae; Muscle, Skeletal; Postoperative Complications; Ribs; Scoliosis; Thoracic Vertebrae; Torque

A biomechanical lumbar spine model was constructed to simulate three-dimensional spinal kinematics under the application of pure moments. Parametric analysis of the model allowed for the estimation of how much of the coupled motions could be predicted by the lumbar lordosis and the intrinsic mechanical properties of the spine.. To evaluate the relative effects of lordosis and intrinsic mechanical spine properties on the magnitude and direction of coupled rotations.. Clinical evidence suggests that abnormal coupled motion in the lumbar spine may be an indicator of low back disorders.. The biomechanical lumbar spine model consisted of five vertebrae separated by intervertebral joints that provided three rotational degrees of freedom. In vitro experimental data, obtained from nine fresh-frozen (L1-S1) cadaveric specimens, were used to establish the mechanical properties of the intervertebral joints. Two different submodels were considered in simulating the three-dimensional intervertebral rotations in response to the applied moments. In the first, it was assumed that the coupled motions were generated solely as a result of the vertebral orientation caused by lordosis. In the second, additional intrinsic motion coupling was assumed.. Intervertebral coupling was partially predicted by lumbar lordosis; however, the inclusion of intrinsic mechanical coupling dramatically improved the simulation of the intervertebral rotations (root mean square error < 1 degree). Comparison of the results from the two models demonstrated that the lumbar lordosis and intrinsic mechanical properties of the spine had about an equal effect in predicting the coupling between axial rotation and lateral bending. In contrast, coupled flexion, associated with lateral bending, was almost fully accounted for by the presence of lumbar lordosis.. The lumbar lordosis and intrinsic mechanical properties of the spine were equally important in predicting the magnitude and direction of the coupled rotations.

Topics: Adult; Biomechanical Phenomena; Humans; Lordosis; Lumbar Vertebrae; Middle Aged; Models, Biological; Posture; Rotation; Torque