Joint Orientation Research Articles

Structural controls on groundwater inflow analysis of hardrock TBM

Results of analyses on localized jointing system are presented to study the link of groundwater inflow and joint orientations along the 2000 m excavation of Tunnel Boring Machine (TBM-1) site, Kara...

Kinematic Model for Robotic Terrestrial Locomotion Inspired in Doves (Columba livia)

Objectives: In this work we create and implement a terrestrial locomotion model inspired in Dove waking scheme and Craig nomenclature for biped robot movement design. Methods: For the model implementation we use the Craig method to obtain the transformation matrix that describes position and orientation of leg joints in Doves. We obtain biological experimental results in a group of Doves (Columbia livia) in order to contrast and complement previous work in terms of energy efficiency. Findings: We propose kinematic models for slow and moderate pace, which were evaluated through energy efficiency analysis. Application: The model offers an alternative for design of mobile robots where the locomotion is performed in irregular terrains since the biped model proposed here, has just two discrete support points in comparison with other types of locomotion such as wheels. Keywords: Biped Locomotion, Biped Robotic, Bio-mechanical Motion, Craig Nomenclature, Denavit Hartenberg

The effect of solder paste volume on surface mount assembly self-alignment

In surface mount assembly, the consistency of solder paste volumes and the placement of the components play a vital role in the movement of the chip components when they go through the reflow soldering process. These movements may lead to common assembly defects such as overhanging, tilting, nonwetting, and tombstoning. Components to be assembled in surface mount assembly have self-alignment nature, which is driven by the total internal energy including gravitational energy, surface tension energy, etc. in the molten solder attributed to various factors. The factors include 1) solder paste composition, surface energy, gravity; 2) process variations such as solder paste volume, solder paste location, the inequality of solder paste volumes at the two terminals of the passive component, and components location and orientation; 3) design parameters such as pad dimension, pad-to-pad spacing, and pad surface finish.In this research, energy-based three-dimensional model is created to predict solder joint profile (shape). Three types of passive chip component are chosen to be the modelling examples to investigate the component self-alignment performance during the reflow soldering process. By nature, the molten solder being a bulk fluid always tends to minimize its internal energy towards mechanical equilibrium and it causes the passive component to move to the state of minimal energy. This movement leads the component to self-align. Thus, by creating an energy minimization model, we can simulate the process of component self-alignment and predict the solder joint profile, final location, and orientation of the passive component.Experimental studies are performed to develop a data-driven prediction model and are compared with the simulated component for validation. The passive components are placed with intended misplacements and their positions are measured before and after soldering. A wide range of surface mount assembly imperfections are considered and intentionally studied to achieve a powerful dataset and better convergence.

Posttraumatic distal radius growth arrest treatment by ilizarov distraction osteogenesis

Background: Posttraumatic distal radius growth arrest is a challenging orthopedic condition, due to a combination of several deformity components including shortening, angulation and joint line malorientation. It can drastically affect both the function and the shape of the wrist and forearm. However, little has been written about this problem. Patients and Methods: In this retrospective study, seven adolescent patients were operated in our department. All had posttraumatic distal radius growth arrest that resulted in shortening with or without angular deformity. The management consisted of distal radius metaphyseal osteotomy and distraction osteogenesis using Ilizarov frame. The patients' ages ranged from 12 to 15 years. The mean shortening of the radius was 2.2 cm. Correction was assessed radiologically (radial length, joint orientation line) and clinically by Mayo Wrist Score. Results: The mean external fixation time was 2.4 months (range from 2 to 3 months). The mean total treatment time was 12.3 weeks (range from 12 to 16 weeks). The mean bone healing index was 1.13 months/cm. The Mayo Wrist Score mean was 85.7 (range: 75–95) points. According to the Mayo Wrist Score, results were excellent in three patients, good in three patients, satisfactory in one patient with no unsatisfactory results. Superficial pin tract infection occurred in all cases and was managed without further sequelae. Conclusion: Distraction osteogenesis, by Ilizarov external fixator, addresses the sequelae of posttraumatic distal radius growth arrest by restoring the normal anatomy in a controlled biological manner, without further grafting procedures through a minimally invasive approach.

Influence of Joint Orientation on the Behavior of Dam Foundation Resting on Jointed Rock Mass Under Earthquake Loading Condition

In this article, the effect of an intact rock foundation and foundations with different single rock joint inclinations (0°, 30°, 60°, 90°) on the dynamic response of the concrete gravity dam under strong earthquake ground motion is investigated. Discrete element analyses are carried out using UDEC to study the stress-deformation behavior of dam for two specific dynamic load combinations (LC), i.e. considering the dead weight of the dam having an empty reservoir with earthquake loading (LC-D) and considering the dead weight of the dam along with hydro-dynamic force with earthquake load (LC-E) as per IS: 6512. From the results, the compressive stresses are found maximum at the heel of the dam for LC-D and maximum at the toe for LC-E. The dam foundation with 60° joint inclination was found most critical in terms of possessing maximum compressive stresses among all other cases. Dam foundation with a horizontal (0°) set of joints exhibits maximum crest displacement and base sliding. Foundations with 60° and 90° joint sets are found to undergo lower base sliding compared to other joint sets.

Pre-therapeutic Device for Post-stroke Hemiplegic Patients’ Wrist and Finger Rehabilitation

Background/Objectives: This paper suggests a pre-therapeutic device for post-stroke hemiplegic patients’ wrist and finger rehabilitation both to decrease and analyze their muscle tones before the main physical or occupational therapy.Method/Statistical Analysis: We designed a robot which consists of a BLDC motor, a torque sensor, linear motion guides and bearings. Mechanical structure of the robot induces flexion and extension of wrist and finger (MCP) joints simultaneously with the single motor. The frames of the robot were 3D printed. During the flexion/extension exercise, angular position and repulsive torque of the joints are measured and displayed in real time.Findings: A prototype was 3D printed to conduct preliminary experiment on normal subject. From the neutral joint position (midway between extension and flexion), the robot rotated 120 degrees to extension direction and 30 degrees to flexion direction. First, the subject used the machine with the usual wrist and finger characteristics without any tones. Second, the same subject intentionally gave strength to the joints in order to imitate affected upper limb of a hemiplegic patient. During extension exercise, maximum repulsive torque of the normal hand was 2 Nm whereas that of the firm hand was almost 5 Nm. The result revealed that the device was capable enough to not only rotate rigid wrist and fingers with the novel robotic structure, but also present quantitative data such as the repulsive torque according to the joint orientation as an index of joint spasticity level.Improvements/Applications: We are planning to improve the system by applying torque control and arranging experiments at hospitals to obtain patients’ data and feedbacks to meet actual needs in the field.

Fusion of Artificial Intelligence in Neuro-Rehabilitation Video Games

In this paper, an intuitive neuro-rehabilitation video game has been developed employing the fusion of artificial neural networks (ANNs), inverse kinematics (IK), and fuzzy logic (FL) algorithms. The embedded algorithms automatically adjust the game difficulty level based on the player’s interaction with the game. Moreover, it is manifested as an alternative approach for possible movements to improve incorrect positioning through real-time visual feedback on the screen; 52 participants volunteered to engage in the program. Motor assessment scale (MAS) was determined to assess the participants’ functional ability pre- and post-treatments. The system input is received via the Microsoft Kinect, a foot Pedal (Saitek), and the Thalmic Myo armband. The ANN classifier integrates the limb joints orientation, angular velocity, lower arms’ muscle activity, hand gestures, feet sole (plantar) pressure parameters, and the MAS scores to learn from data and predict the improvement following the intervention. The fuzzy input generates a crisp output and provides a personalized rehabilitation program with the potential to be integrated into clinical protocols. Experiments to obtain the input signals and desired outputs were conducted for the learning and validation of the network. The networks pattern recognition, self-organizing map, and non-linear auto-regression analysis performed using feed-forward and Levenberg–Marquardt backpropagation (LMBP) procedure. The results showed the effectiveness of the non-linear auto-regression using the optimized LMBP algorithm to classify and visualize the target categories. Furthermore, the state of the network demonstrates the prediction accuracy exceeding 94%. Clustering algorithm grouped the data based on the similarity. Self-organizing map trained the network to learn the topology of samples with high correlation, presented outputs with high achievement.

Effect of finger joining on flexural strength of commonly used timber species in Sri Lanka

The variation of flexural strength of seven timber species mainly used for furniture industry in Sri Lanka was studied. Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) were measured without finger joint and with finger joint specimens of timber species. Finger joint technique is used to eliminate wood defects which weaken the strength of sawn wood plank and used. This paper gives comparison study of finger jointed and un-jointed seven wood species, tested under three point bending test. BS 373: 1957 and BS EN 15497:2014 were used as standards for tests. Vertical finger joint orientation and 13 mm finger joint length were used in this study. The tests for mechanical properties were performed by using a Universal Testing Machine (UTM 100 PC). The parameters were analyzed by using ANOVA and means were separated by Duncan's Multiple Range Test at 0.05 significant levels in SAS. It was found that control (un-jointed solid wood) samples gave the highest flexural strength than finger-jointed specimens and it was also observed that Kumbuk timber species was showed the highest MOE in 13 mm finger-jointed specimens comparing control specimens. The highest flexural strength loss percentage was obtained from Satin species. The MOE of finger-jointed Kumbuk was higher than clear Kumbuk specimens and least strength loss percentage of MOR (46.08 %) was obtained from Mahogany species.

Potential pathological mechanisms of L3 degenerative spondylolisthesis in lumbar spinal stenosis patients: A case–control study

BackgroundDegenerative spondylolisthesis (DS) occurs mostly at L4. However, there are a small number of patients in whom it occurs only at L3. Accordingly, past reports elucidating the factors of DS have been primarily concerned with L4 DS, and few reports are available on DS at L3. The objective of this study was to compare the differences between lumbar spinal stenosis patients with or without L3 DS and to identify the possible pathological mechanisms of their L3 DS. MethodsAmong the 369 patients with lumbar spinal stenosis who underwent lumbar surgery, we assessed 25 patients who had DS only at L3 and compared them against 50 other age- and gender-matched lumbar spinal stenosis patients without any DS. The following radiographic parameters: pelvic incidence, sacral slope, pelvic tilt, L3 slope, L4 slope, L5 slope, and lumbar lordosis were measured on radiographs. The orientation of facet joints and disc heights were measured via computed tomography. ResultsImaging findings showed that the L3, L4, and L5 slopes in the L3 DS group were significantly greater than in the non-DS group, and only L3/4 facet joints in the L3 DS group were significantly more sagittally oriented than in the control group. The number of patients with low disc heights at L4/5 in the L3 DS group was significantly greater than in the control group. ConclusionsThe results suggested that the greater lumbar slope, including L3 together with more sagittally oriented facet joints only at L3/4 and not at L4/5, may lead to DS only at L3.

Group Sparse Regression-Based Learning Model for Real-Time Depth-Based Human Action Prediction

This paper addresses the problem of predicting human actions in depth videos. Due to the complex spatiotemporal structure of human actions, it is difficult to infer ongoing human actions before they are fully executed. To handle this challenging issue, we first propose two new depth-based features called pairwise relative joint orientations (PRJOs) and depth patch motion maps (DPMMs) to represent the relative movements between each pair of joints and human-object interactions, respectively. The two proposed depth-based features are suitable for recognizing and predicting human actions in real-time fashion. Then, we propose a regression-based learning approach with a group sparsity inducing regularizer to learn action predictor based on the combination of PRJOs and DPMMs for a sparse set of joints. Experimental results on benchmark datasets have demonstrated that our proposed approach significantly outperforms existing methods for real-time human action recognition and prediction from depth data.

Vertebral three-dimensional motion characteristics of adjacent segments in patients with isthmic spondylolisthesis in vivo

To observe vertebral three-dimensional motion characteristics of adjacent segments in patients with symptomatic L 4 isthmic spondylolisthesis (IS). Fourteen symptomatic L 4 IS patients who underwent surgery treatment (trial group) and 15 asymptomatic volunteers without back pain and other lesions of spine (control group) were recruited. There was no significant difference in gender, age, body mass index, and bone mineral density between the two groups ( P>0.05). The three-dimensional reconstruction model of lumbar spine was acquired from the thin slice CT of the lumbar spine of the subjects by combining dual-X-ray fluoroscopy imaging system with spiral CT examination. The model was matched to the double oblique X-ray fluoroscopy images captured by dual-X-ray fluoroscopy imaging system at different active positions of the lumbar spine to reproduce the three-dimensional instantaneous of lumbar spondylolisthesis at different state of motion. The motion and relative displacement of adjacent segments (L 3, 4 and L 5, S 1) of spondylolisthesis were measured quantitatively by establishing a three-dimensional coordinate system at the geometric center of the vertebral body. The results were compared with those of the control group. When L 3, 4 in the control group were flexed flexion-extension, left-right twisting, and left-right bending, and when L 5, S 1 in the control group were flexed left-right twisting and left-right bending, the activity along the main axis of motion (main axis of motion) tended to increase compared with that along the corresponding coupled axis of motion (secondary axis of motion); however, this trend disappeared in the trial group, and the main and secondary movements were disordered. Because of the coronal orientation of the facet joints of L 5, S 1, the degree of motion along the main axis of motion decreased during flexion and extension, but this trend disappeared in the trial group. Compared with the control group, L 3, 4 in the trial group exhibited displacement instability in flexion-extension, left-right twisting, and left-right bending ( P<0.05); there was no significant difference in the relative displacement of L 5, S 1 intervertebral bodies along x, y, and z axes between the trial group and the control group in flexion-extension, left-right twisting, and left-right bending curvature ( P>0.05). Patients with symptomatic L 4 IS have disorders of primary and secondary movement patterns in adjacent segments, while IS showed significantly displacement instability in L 3, 4 and significantly decreased motion in L 5, S 1.

Investigating the effect of discontinuity geometrical parameters on the TBM performance in hard rock

By technological advancements, mechanization is also growing in engineering activities. A prominent example is the extensive use of tunnel boring machines (TBM) in the tunneling projects. The main motivations for using these machines are the lower cost and time saving, which are achieved with proper prediction of TBM performance. The prediction is influenced by various factors, such as intact rock parameters (compressive strength, tensile strength, brittleness), jointing parameters and geometrical parameters of the machine, including disc geometry and the spacing of discs from each other. In this paper, we study the TBM performance in real-scale, by simulation of cutterhead in real dimensions. Among the effective factors, the influence of orientation and spacing of joints on the performance of TBM in hard rock is investigated using numerical modeling. The results indicate that the 60° angle of the joints with the advance axis of TBM has the most effect on the TBM performance; and zero angle of the joints has the least effect. Also, regarding the spacing of joints, 400 mm spacing has been known as critical spacing. By increasing the spacing value above 400 mm, there is no changes in TBM performance. These results confirm previous studies conducted on this subject. Generally, based on the joint orientation, the ease of cutting in jointed rock mass increases about 30–70 percent.

Effects of Jointed Rock Mass and Mixed Ground Conditions on the Cutting Efficiency and Cutter Wear of Tunnel Boring Machine

The cutting efficiency and wear of tunnel boring machine (TBM) cutters are two important parameters commonly used to estimate the boring performance and lifetime of the TBM in the tunneling process. These problems have been investigated by several researchers, whereas the influence of jointed rock mass and mixed ground condition on the cutting efficiency and cutter wear remains insufficiently understood. This study aims to elucidate the influence of rock mass and ground parameters on the cutting efficiency and cutter wear of the TBM by conducting a series of newly developed rolling boring tests on prefabricated joint sandstone samples with different orientations, spacings, and interlayers. Moreover, a numerical simulation is implemented through ANSYS software to verify the rationality of experimental results. The experimental and numerical results indicate that the optimal joint orientation is 30° for the TBM to intrude into a jointed rock mass. As joint spacing increases, the cutting efficiency decreases and the cutter wear increases. Furthermore, specific energy (SE) and cutter wear simultaneously reach their maximum values when the rock abrasivity index (RAI) is 60. Both the specific energy and cutter wear decrease with increasing specific strength. For the rock mass with a soft interlayer in mixed ground, the optimal dip angle is 45°. Additionally, the fitting formulas of SE and cutter wear in mixed ground are proposed to quantitatively illustrate the effect of RAI and interlayer strength on the cutting efficiency and cutter wear. The present study provides an improved understanding of rock-breaking mechanics, thereby making it possible for designers to adjust their design to enhance the TBM cutting efficiency.

Joint Elasticity Effect on the Failure Behaviours of Rock Masses using a Discrete Element Model

It is widely accepted that the mechanical properties and failure behaviours of a rock mass are largely dependent upon the geometrical and mechanical properties of discontinuities. The effect of joint elasticity on the failure behaviours of rock masses is investigated using a discrete element model, namely, the synthetic rock mass model. Here, uniaxial compression tests of the numerical model are carried out for the rock mass model with a persistent joint to analyse the role of joint elasticity in the failure process with various joint orientations, β. A strong correlation between the joint elasticity and failure strength is found from the simulation results: a positive relationship when the joint orientation β &lt; φ j ; a negative relationship when the joint orientation φ j &lt; β &lt; 90 ° ; and a very limited effect when the joint orientation β = 90 ° . Additionally, it is shown that the joint elasticity is the governing factor in the transition of failure modes, especially from the sliding failure mode along the joint to the mixed sliding-tensile failure mode.

Joints and confining stress influencing on rock fragmentation with double disc cutters in the mixed ground

Complex geological factures are often encountered in the tunneling boring machine (TBM) excavation leading to many serious problems, especially the mixed ground conditions involving in the different geological properties should be paid more attention. To better investigate the effects of the mixed ground characteristics on rock fragmentation process by double TBM cutters, the model embedded crack propagation algorithm combined with M-C failure criterion has been calibrated for the mixed ground by double disc cutters. And then, the cutting simulations are conducted by 3DEC considering joint spacing, joint orientation and confining stress. The results under different conditions indicate that smaller joint spacing implying weaker properties favorably cause more cracks initiation and propagation by double cutters, and the cracks are tending to propagate along the joint plane and facilitate the rock chips beneath the cutters. And it is found that the joints are inclined to the soft rocks, more shear failure induces more cracks propagating inside the soft rocks, indicating that these rocks can be fragmented more completely. Meanwhile, with the increase of confining stress, rock fragmentation is more difficult resulting in the decrease of the cutting efficiency, especially the cracks induced by shear failure in soft rocks propagating along the free surface and interface cannot link the minor cracks by tensile failure in hard rocks to form rock chips. Furthermore, as noted from the variation of fragmentation load and specific energy under different conditions, smaller joints spacing causes smaller fragmentation load and specific energy to improve the cutting efficiency, however, greater confining stress gives more restrain for the cracks propagation, and the rock chips cannot effectively form between two types of rocks, resulting in lower fragmentation efficiency. And in addition, the optimal cutter spacing has also been analyzed under above conditions, which helps to provide appropriate measures for improvement of rock fragmentation efficiency and TBM performance during the TBM excavation process.

Changes in the Superior Zygapophyseal Joints in the Lower Thoracic and Upper Lumbar Vertebrae in Babylon Population

Background: The articular processes of the vertebral column play a role in weight transmission as well as in governing the range and direction of movement between two vertebrae. The pattern of changes of orientation of these particular processes from thoracic to lumbar type was seldom mentioned in anatomical textbooks.Objective: to study the pattern of changes of zygapophyseal joints in local citizen in Babylon Province.Methodology: 140 persons (80 female and 60 male) aged 20-66 years (mean 46.84± 14.438) attending to radiology department in Marjan Teaching Hospital, Babylon, Iraq, were participated in this study, they were investigated to be free from any congenital anomaly or pathological change. Using computed tomography with axial sections, the lower four thoracic and upper lumbar vertebrae. The zygapophyseal joints were carefully observed to detect the site of changes in orientation from thoracic to lumbar type.Results:The present study revealed that there were two types of change in the orientation of zygapophyseal joint were observed; gradual and sudden.21.42% of subjects showed gradual changes in orientation of zygapophyseal from thoracic type to lumbar type, with female ratio higher than male. The transition started mainly at T11-L2, some subjects showed transition at T12-L2.While 78.58% of subjects showed sudden changes; mainly at T12-L1, and to a lesser extent at T11-T12.Conclusions:In the group of people who were studied it was clear that the change of the superior zygapophyseal joint from flat, posterolaterally oriented which is thoracic type to curved, posteromedially oriented which is lumbar type is more likely to occur as sudden change rather than the gradual change which observed in about one-fifth of the population.

Effect of Joint Geometrical Parameters on Hydraulic Fracture Network Propagation in Naturally Jointed Shale Reservoirs

The presence of a significant amount of discontinuous joints results in the inhomogeneous nature of the shale reservoirs. The geometrical parameters of these joints exert effects on the propagation of a hydraulic fracture network in the hydraulic fracturing process. Therefore, mechanisms of fluid injection-induced fracture initiation and propagation in jointed reservoirs should be well understood to unleash the full potential of hydraulic fracturing. In this paper, a coupled hydromechanical model based on the discrete element method is developed to explore the effect of the geometrical parameters of the joints on the breakdown pressure, the number and proportion of hydraulic fractures, and the hydraulic fracture network pattern generated in shale reservoirs. The microparameters of the matrix and joint used in the shale reservoir model are calibrated through the physical experiment. The hydraulic parameters used in the model are validated through comparing the breakdown pressure derived from numerical modeling against that calculated from the theoretical equation. Sensitivity analysis is performed on the geometrical parameters of the joints. Results demonstrate that the HFN pattern resulting from hydraulic fracturing can be roughly divided into four types, i.e., crossing mode, tip-to-tip mode, step path mode, and opening mode. As β (joint orientation with respect to horizontal principal stress in plane) increases from 0° to 15° or 30°, the hydraulic fracture network pattern changes from tip-to-tip mode to crossing mode, followed by a gradual decrease in the breakdown pressure and the number of cracks. In this case, the hydraulic fracture network pattern is controlled by both γ (joint step angle) and β. When β is 45° or 60°, the crossing mode gains dominance, and the breakdown pressure and the number of cracks reach the lowest level. In this case, the HFN pattern is essentially dependent on β and d (joint spacing). As β reaches 75° or 90°, the step path mode is ubiquitous in all shale reservoirs, and the breakdown pressure and the number of the cracks both increase. In this case, β has a direct effect on the HFN pattern. In shale reservoirs with the same β, either decrease in k (joint persistency) and e (joint aperture) or increase in d leads to the increase in the breakdown pressure and the number of cracks. It is also found that changes in d and e result in the variation in the proportion of different types of hydraulic fractures. The opening mode of the hydraulic fracture network pattern is observed when e increases to 1.2 × 10−2 m.

The Relationship of Facet Joint Orientation and Tropism with Lumbar Disc Herniation and Degenerative Spondylolisthesis in the Lower Lumbar Spine.

Study DesignRetrospective study.PurposeThis study aimed to clarify the relationship of both facet tropism (FT) and the sagittally aligned facet (SAF) joint with lumbar disc herniation (LDH) and degenerative spondylolisthesis (DS).Overview of LiteratureDespite several studies conducted, there is no consensus on the association of the SAF joint and FT with DH and DS.MethodsBetween June 2015 and December 2017, magnetic resonance imaging scans of 250 consecutive patients who underwent surgery for LDH and DS were analyzed. The facet angles at all the lower lumbar levels were calculated, and SAF and FT were noted. The relationship between the side of disc herniation and that of the SAF joint were also determined. Statistical analysis was performed, and the relation of SAF and FT to LDH and DS was noted.ResultsWe observed a positive relationship between SAF and LDH at L4–5 and L5–S1 with a p-value of 0.02 (<0.05). FT demonstrated a positive association with LDH at L4–5 (p=0.047) but not at L3–4 or L5–S1. SAF demonstrated a positive relationship with DS at L3–4 (p<0.001) but not at L3–4 or L5–S1. FT demonstrated a significant relation with DS at L4–5 (p<0.001), whereas no positive association was observed at L3–4 and L5–S1.ConclusionsThe L4–5 level demonstrated a significant association with SAF and FT in LDH and DS. Moreover, SAF at L5–S1 demonstrated a positive association with LDH. These findings provide useful information for future longitudinal studies to elucidate the possible causes for such phenomena.

Which Body Position Is the Best for Chest Wall Motion in Healthy Adults? A Meta-Analysis.

Chest wall motion is a vital component of the respiratory system. Body position changes disturb joint orientation around the chest wall and results in performance modifications of respiratory muscles and movement surrounding the rib cage and the abdomen. Body position is a priority treatment for preserving and promoting chest wall motion. The objective of the study was to conduct a meta-analysis to provide insight into which body position most effectively improves chest wall motion. Medical literature databases were systemically searched up to January 31, 2018. Methodological quality was evaluated by using a checklist for measuring quality. A meta-analysis was performed to evaluate the effects of body positions on chest wall motion. The quality of evidence was judged by using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach. Six studies (5 high- and 1 low-quality) were identified. Our results showed that the sitting position provided greater improvement in chest-wall diameter changes and volume related to rib-cage function versus other body positions (very low to moderate evidence). The supine position demonstrated greater enhancement of chest-wall-diameter changes and volume in the part of the abdomen than the other body positions with very low to moderate evidence. The results of this review indicated that the sitting position improved the rib-cage compartment of the chest wall, whereas the supine position resulted in the superior enhancement in the part of the abdomen relative to other body positions. These changes in the body position could have some effect on the movements of the rib cage and abdomen and the variations in lung volumes, which need to be interpreted with caution when considering implementation in the clinical setting.

Age-related changes in axial and sagittal orientation of the facet joints: Comparison with changes in degenerative spondylolisthesis

BackgroundDespite facet joints being three-dimensional structures, previous computed tomography and magnetic resonance imaging studies have evaluated facet joint orientation in only the axial plane. Facet joint orientation in the sagittal plane has rarely been studied using these imaging techniques. The aim of this study was to elucidate facet joint orientation in both the axial and sagittal planes on computed tomography. MethodsA total of 568 patients (343 men, 225 women) (excluding orthopedic outpatients) for whom abdominal and pelvic computed tomography scans were obtained at our hospital between September 2010 and October 2012 were included. Mean age was 63 (range 21–90) years. Patients were divided into a degenerative spondylolisthesis group (67 patients; 30 men, 37 women) and a control group (313 patients; 313 men, 188 women). Facet joint orientation was evaluated in the control group according to patient age (≤50, 51–60, 61–70, or ≥71 years). The findings in the control group were then compared with those in the degenerative spondylolisthesis group. The orientation of the lumbar facet joints at each level was measured in the axial and sagittal planes on computed tomography images. ResultsFacet joint angles decreased with age at L4/5 and L5/S1 in women in the axial plane and at L4/5 in men and L3/4 and L4/5 in women in the sagittal plane. The variation in facet joint angle was greatest at L4/5 in women. Patients with degenerative spondylolisthesis showed more sagittally and horizontally oriented facet joints in the axial and sagittal planes; facet tropism showed an association with degenerative spondylolisthesis in the axial plane. ConclusionsThe axial and sagittal orientation of facet joints in the lower lumbar vertebra, especially L4/5, was negatively correlated with age. This finding could help to explain why older people are more prone to degenerative spondylolisthesis.