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Functional Rehabilitation
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
The neck is composed of seven cervical vertebrae, the first two of which are of particular interest. The atlas (C1) holds the weight of the head, the boney articulation allows a slight nodding motion. The axis (C2) sits underneath the atlas and is almost like a circular disk with a vertical protuberance called the dens. The atlas spins on the dens creating a great deal of rotational motion.
Difficult areas in forensic neuropathology
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
Christopher Milroy, Helen Whitwell
The most common neck injury is fracture dislocation of the atlanto-occipital junction. This injury is inevitably fatal, and injury is most frequently encountered in motorcyclists but is seen in pedestrian fatalities. Other damage to the cervical vertebrae may be seen as well as fractures or dislocation to thoracic or lumbar spine (see also Chapter 16).
Work stress induced musculoskeletal disorders in construction
Published in Imriyas Kamardeen, Work Stress Induced Chronic Diseases in Construction, 2021
Musculoskeletal disorders (MSDs) is an umbrella term for injuries or disorders of muscles, nerves, tendons, joints, cartilage and spinal discs in the human body. Work-related musculoskeletal disorders (WMSDs) are conditions in which the work environment and performance of work contribute significantly to the condition and/or the condition is made worse or persists longer due to work (Centers for Disease Control and Prevention 2018). Common types of WMSDs are (Korhan and Memon 2019): cervical vertebrae (symptom: neck pain/stiff neck)rotator cuff tendinitis (symptom: shoulder pain)lower back painarthritis (pain, swelling and inflammation in and around the joints and other body organs)carpal tunnel syndrome (symptoms: numbness, tingling or burning sensation in the palms, fingers and wrists)elbow painknee painhernia.
Comparison of immediate effects of sling-based manual therapy on specific spine levels in subjects with neck pain and forward head posture: a randomized clinical trial
Published in Disability and Rehabilitation, 2020
Forward head posture (FHP) is identified as the flexion of the lower cervical spine (C4-7) along with the extension of the upper cervical spine (C1-3), with an overall increase in the cervical curve, referred to as hyperlordosis [2]. This abnormal position appears mainly in office workers and students in the modern society. It has been reported that as the head position increases, the tension of the muscles that maintain the posture of the neck increases and the joint compression force of the cervical vertebra increases [3]. Yip et al. [4] also reported that the severity of neck pain and dysfunction levels increased as the head shifted forward. In addition, extension of the craniocervical area has been reported to increase the muscle activity of the temporal and masseter muscles due to the change in the position and movement of the mandible in the chewing process [2].
A multi-body model for comparative study of cervical traction simulation – comparison between inclined and sitting traction
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Lawrence K. F. Wong, Zhiwei Luo, Nobuyuki Kurusu, Keiji Fujino
Eight rigid bodies are used to represent the head and the seven pieces of the cervical vertebrae (C1–C7) in the cervical spine. Each intervertebral joint is modelled as non-linear viscoelastic material in the flexion/extension direction and with linear spring-damper in the tension/compression direction and anterior/posterior shear direction. Figure 2 illustrates structure of the intervertebral joint that represents the tension/compression, flexion/extension and posterior ligament. The biomechanical parameters, including stiffness, damping, ROM, are referenced from published head-neck simulation model studies (de Jager 1996; Yoganandan et al. 2000; van Lopik and Acar 2007) and cadaver sample studies (Moroney et al. 1988; Yoganandan et al. 1996). The simulation model is developed using C++ in Microsoft Visual Studio 2015 using the Bullet physics library as the physics engine. The timestep is fixed at 1/360th second (∼2.78ms). Traction force is applied incrementally within a period of 10 seconds and remains constant until the end of the trial. The period of each simulation trial is 15 seconds. Details regarding the development and validation of the simulation model can be found in the first part of the study (Wong, Luo, Kurusu, et al. 2019).
A multi-body model for comparative study of cervical traction simulation – development, improvement and validation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Lawrence K. F. Wong, Zhiwei Luo, Nobuyuki Kurusu, Keiji Fujino
The structure of the cervical spine model is illustrated in Figure 2. Eight rigid bodies are used to represent the head and the seven pieces of the cervical vertebrae (C1-C7). Each intervertebral joint is modelled as non-linear viscoelastic material in flexion and extension. It is built as a “free joint” element in the simulation. The “free joint” element allows stiffness and damping properties to be assigned to the joint with required number of degrees of freedom of motion. Since traction force is applied symmetrically during cervical traction, lateral shear (i.e. translation along x-axis) is not modelled in the simulation. Also, since the inclined and sitting positions do not cause axial rotation and lateral bending to the cervical spine, these two rotation directions are not modelled. In other words, only anterior/posterior shear, tension/compression and flexion/extension are modelled in the simulation. For the ligaments, a spring element at the spinous process is used to represent the combined behavior of all four posterior ligaments at each cervical level. Since we assume that the subject is in a relaxed state during cervical traction and muscle activation is minimal, thus muscle components are not included in the model. A detailed overview of the joints in the cervical spine is shown in Figure 3.