Sharif Digital Repository

In this project, we use a novel mechanism to control the lumbar rotational profile and also the disc pressure of L3/L4 and L4/L5. Spine, as one of the most important parts of human musculoskeletal system, helps human beings to walk on two feet without much energy consumption. Any problem in this part may cause moving disorders or pain. To heal severe spine disorders, many different methods like surgery and implantation are adopted. To be sure of proper functionality in the human body, these methods should be tested clinically in advance. Cadaver spine testing in vitro, is accepted as a gold standard to evaluate new methods. One of the main challenges facing spine in vitro tests is how to... 

In this study, by dividing spine motion in two part, ordinary movement and initial-final accelerated movement, the commands of CNS are evaluated by optimization methods to find synchronous and time varying synergies. Spine, which is a complex structure of vertebrae and cartilage, has been modeled by a 3D inverted pendulum with a ball and socket joint at L4/L5 incorporated with 18 muscle fascicles. Planning of point-to-point spine motion is performed by optimal control method in combined with cost function of kinematics and kinetic features that available in spine structure. In the second step, coactivation of muscles is predicted by utilizing static optimization along with stability... 

There is a large, at times contradictory body of investigations relating low back pain and spinal curvature in sagittal plane. The previous studies have not been subject-specified, and they have not considered the active tissues in the models. The mechanical load has a significant impact on the prevalence of low back pain and the geometry of lumbar spine in the sagittal plane is one of the most important characteristics in determining the load sharing of the spine. Thus, it is essential to know how the geometry load affects the load sharing of the lumbar spine. As a matter of fact, the purpose of this project is to know how the geometry of the lumbar spine affects the load sharing. Thus,... 

Etiological studies proves the fact that Low Back Pain (LBP) is one of the most expensive and prevalent desease all over the world. This fact illustrates the reqiurment of the special effort in ordet to reducing the pain due to this problem. Finite element modeling of human spine is one the suitable methods to simulate the behavior of human spine in different loading conditions. These conditions could be different daily occupational tasks. There is two general viewpoint toward finite element modeling of human spine. The fisrt method focuses on the detailed geometry and mechanical properties of spine, while the other complexities such as detailed muscle forces are overlooked. The latter... 

Posterior lumbar surgery is often associated with extensive injuries to back muscles. In this thesis, the effect of such iatrogenic injuries in some patients was examined. For this purpose, the CSA of back muscles in 6 patients were measured using MR scan. To examine any natural change in CSAs of healthy people or instrument errors, same measurement were carried out on 10 healthy volunteers. In addition, a detailed anatomical model of an intact human spine was developed. With the aim of experimental studies and intact model, the post-operative model of patients was also developed. These two models were used to quantizing the change in activity of back muscles during some symmetric, normal... 

In present study we are going to introduce a biomechanical model of lumbar spine with using finite element method and use it for evaluating the behavior of spine under different loading conditions.Spine as the main part of muskloskeletal system of human body is tolerating various forces during daily activities.So it's important to know about different approaches for studing the loading conditions wich is using for evaluating the behavior of lumbar implants. In other words in order to obtain correct outputs we need to simulate the real condition in the experiments. We can use biomechanical models in order to comparison the different approaches  

Spine is one of the most important musculoskeletal systems of the human body. Any problem which is related to this part of human body causes pain and disability. Spinal compression forces are one of the main reasons of this disability and pain. It is assumed that intra-abdominal pressure causes spinal unloading in lifting. Studies usually don’t consider the role of intra-abdominal pressure and introduce it as an effective parameter which can increases spinal stability and influences spinal mechanics.Generation mechanism of intra-abdominal pressure remain enigmatic, studies that advocate the unloading effect of IAP usually consider a raise in IAP to be primarily due to the activity of... 

Epidemiological studies have identified manual material handling and lifting as risk factors in occupational low back pain (LBP). There are many lifting analysis tools to estimate the risk of injury during a specific lifting task. One for using these tools, needs to know the limitations of each tool and be noticed where a tool cannot be used. The purpose of this study is to compare different biomechanical models of lumbar spine and find out their characteristics.Five models are chosen for this study which are: the University of Michigan’s Static Strength Prediction Program ( ) software, the revised Hand-Calculation Back Compressive Force (HCBCF) equation, the simple polynomial equation of... 

One of the most important parts of the human’s body is spine. Its anatomy is very complex and has many degrees off freedom. Many kinds of diseases might occur for this part. One of the ways of treatment for this part is surgery that it has different types. In the past decades the surgeries have been done very simple without the help of computers or robots. In other words the surgeon did the surgery with no use of lateral tools. For this reason the error in those surgeries was high. Doing a surgery on the spine level needs a special attention. As the technology improved very much in the last 2 decades the amount of errors has been reduced and various kinds of techniques came in the scene to... 

Disorders of the lumbar spine are prevalent within the realm of musculoskeletal issues, emphasizing the importance of investigating contributing factors. This research focuses on assessing how flexible footwear influences the kinematics and dynamics of the vertebral column during drop vertical jump. The study involves mechanical tests on various footwear types, including simple, flexible and re entrant shoes with differing levels of rigidity. Bending tests were performed on simple and flexible shoes with hardness of 50 Asker C and flexible shoes with hardness of 40 Asker C. Additionally, compression tests were carried out on all soles at two different angles. The Bending tests revealed that,...