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Designing for Upper Torso and Arm Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The mechanical stresses on the sacral and coccygeal spinal elements are different from those in the thoracic and lumbar spine. The differences in stress lead to marked form variations of these lower vertebrae, compared to the relatively consistent forms of the thoracic and lumbar vertebrae. Below L5 there is little to no vertebral motion. The five sacral vertebrae are fused into a shield-shaped structure, the sacrum (Figure 4.8). Remnants of the S1 vertebral body and sacral vertebral spinous processes can be seen within the sacrum (Figure 4.7). The sacroiliac joint, between the lateral aspects of the sacrum and the iliac bones of the pelvis, joins the axial and appendicular skeletons in the pelvis. The tailbone or coccyx varies from one person to another with three to five coccygeal vertebrae. These very small vertebrae may or may not be fused together. The coccyx, fused or not, curls toward the front of the body from the tip of the sacrum. Injuries to the coccyx can be painful. Protective gear, such as football tailbone pads, have been designed to protect this vulnerable area of the spine (Figure 4.8).
Reduction and Fixation of Sacroiliac joint Dislocation by the Combined Use of S1 Pedicle Screws and an Iliac Rod
Published in Kai-Uwe Lewandrowski, Donald L. Wise, Debra J. Trantolo, Michael J. Yaszemski, Augustus A. White, Advances in Spinal Fusion, 2003
Kai-Uwe Lewandrowski, Donald L. Wise, Debra J. Trantolo, Michael J. Yaszemski, Augustus A. White
Pedicle screw fixation has been developed as a procedure for posterior internal fixation of the thoracic, lumbar, and lumbosacral spines. In our study the SI pedicle screws were converged medially in a triangular fashion as the anchor of the sacrum. The triangulation has been presented in a biomechanical study to significantly enhance loads on pullouts of the pedicle screws [32]. In addition, the sacral pedicle screws penetrated the anterior cortex of the sacrum to increase the pullout resistance [33]. With regard to another fixation anchor for iliosacral fixation, we utilized a rod inserted between the inner and outer cortices of the ilium (Galveston technique). This fixation anchor has been demonstrated in biomechanical studies to be the most stable for lumbosacral fixation among the various fixation procedures [34,35]. The combined use of SI pedicle screws and the Galveston technique, utilized in our series, provided sufficient reduction and good stabilization in the treatment of sacroiliac dislocation. With other posterior sacroiliac fixation techniques using sacral bars and iliosacral screws, reduction must be performed prior to internal fixation. On the other hand, the hybrid anchoring technique, which uses SI pedicle screws and an iliac rod, provides sufficient reduction prior to fixation. From this point of view, the combined use of the SI pedicle screw and the Galveston technique may be superior to other posterior internal fixation procedures for reduction and fixation of sacroiliac dislocation. However, further biomechanical studies are required for comparison of the stabilizing capability with those of other fixation procedures.
in vivo monitoring of peristalsis in the human gut
Published in P. Dakin John, G. W. Brown Robert, Handbook of Optoelectronics, 2017
We have also used our high-resolution catheters to examine the effects of interventions upon colonic function. In patients with fecal incontinence, a novel treatment known as sacral nerve stimulation (SNS) has been shown to dramatically improve the patients’ ability to maintain continence of their stool. However, the action of SNS is still a matter of conjecture. In a recent study on SNS, our data have revealed that in patients with fecal incontinence, this stimulation increased the locally controlled retrograde propagating motor patterns in the distal parts of the colon. This is presumed to reduce premature rectal filling, which in turn helps the patient to maintain continence (Patton et al. 2013).
Analysis of sagittal profile of spine using 3D ultrasound imaging: a phantom study and preliminary subject test
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2020
Timothy Tin-Yan Lee, James Chung-Wai Cheung, Siu-Yu Law, Michael Kai Tsun To, Jason Pui Yin Cheung, Yong-Ping Zheng
Human spine composes of five regions: cervical, thoracic, lumbar, sacrum and coccyx. Thoracic kyphosis and lumbar lordosis are two common sagittal parameters when analyzing sagittal profile. For normal individuals, acceptable ranges for kyphosis and lordosis are between 20–50 degrees and 31–79 degrees, respectively (Bridwell and Bernhardt 1989; Boseker et al. 2000). It is essential to maintain a balanced sagittal spinal profile because an optimal degree of kyphosis and lordosis is necessary to maintain spine motor control with minimum energy expenditure, enhance the load tolerance of the spine and increase spinal muscle efficiency (Kim et al. 2006). From a clinical point of view, a better understanding of the sagittal spinal profile helps to evaluate patients with spinal pathology, assist surgical planning and minimise complications such as spinal deformity issues like sagittal imbalance (Cho et al. 2014).
Office Chair Backrest Height Affects Physiological Responses to Sitting
Published in IISE Transactions on Occupational Ergonomics and Human Factors, 2020
Kayla M. Fewster, Graham Mayberry, Jack P. Callaghan
Lumbar, thoracic, and cervical spine angles were tracked using accelerometers (ADXL335, Analog Devices, Norwood, MA, USA) as inclinometers. Accelerometers were placed over the following landmarks: back of the head (Head), at the level of the seventh cervical vertebrae (Neck), at the level of the first lumbar vertebrae (Lumbar), and sacrum (Pelvis). Calibration trials were performed to normalize flexion/extension angles. These trials included: upright standing, maximum neck flexion and extension, and maximum lumbar flexion and extension. Accelerometer data were sampled at 250 Hz.
Influence of energy absorbers on Malgaigne fracture mechanism in lumbar-pelvic system under vertical impact load
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
K. Arkusz, T. Klekiel, G. Sławiński, R. Będziński
A geometric model of lumbar-pelvic complex (LPC) was elaborated using a computed tomography (CT) scans of a healthy patient, performed using an 8-row spiral CT with accuracy of 2.5 mm. The cortical and trabecular microstructures of the sacrum, the ilium and the fifth lumbar vertebrae were exported to STL files using MIMICS software and further re-meshed using MeshLab software for smoothing individual surfaces. The mesh of finite elements was generated in Ansys 16.2 software as 8-node tetrahedral (245,262 elements).