Anatomy of Neck and Blood Supply of Brain
Sudhir K. Gupta in Forensic Pathology of Asphyxial Deaths, 2022
The cervical vertebrae are seven in number, and among them, the third to sixth vertebrae have characteristic features of cervical vertebrae like spinous processes being short and bifid, articular facets being flat and oval, the transverse process containing the foramen transversarium, etc. The first, second and seventh cervical vertebrae are distinct with each one having peculiar features, like the first vertebra is called Atlas and it lacks a spinous process and is more of a ring with anterior and posterior arch. The second vertebra is called Axis; it acts as a pivot on which the skull and the Atlas move, and it also has an odontoid process that forms a joint with Atlas. The seventh vertebra is called Vertebra prominens and has a very long and prominent spinous process, making it easily palpable under the skin. Radiological examination either with X-ray or CT scan is very useful for determination of fracture dislocations of cervical vertebrae which could be fatal (Figures 2.1a–2.2b).
Neck pain and whiplash
Peter R Wilson, Paul J Watson, Jennifer A Haythornthwaite, Troels S Jensen in Clinical Pain Management, 2008
The most likely lesions that underlie chronic neck pain after whiplash are injuries to the intervertebral disks and zygapophysial joints. Cineradiography studies in normal volunteers undergoing simulated whiplash collisions reveal that at some 100 msec after impact, the cervical spine undergoes a sigmoid deformation, during which the lower cervical vertebrae undergo extension about an abnormal axis of rotation.59 The movement is such that the anterior edges of the vertebral bodies separate and the zygapophysial joints impact (Figure 36.4). These movements indicate that the anterior anulus fibrosus can be sprained while the zygapophysial joints can suffer impaction fractures or contusions to their meniscoids.59 These are the very lesions that have been demonstrated in post mortem studies of victims of motor vehicle accidents.60, 61, 62
NBAS/RALF deficiency
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop in Atlas of Inherited Metabolic Diseases, 2020
Short stature is one of the most frequent findings in NBAS deficiency (Figure 106.2). The affected Yakuts had a mean SDS of height of -4.44 in females and -3.16 in males [1], in our study population, mean height was -2.64 SDS [3], the most severe case known to us however had a severe growth retardation with -6.10 SDS (despite a genetically determined body height of 0.89 SDS) (Figure 106.3). The severity of growth retardation seems to be associated with further skeletal features, such as thin bones and epiphyseal dysplasia with multiple phalangeal pseudo-epiphyses, reminiscent of a disturbance in bone mineralization. Two patients were found to have small cervical vertebrae (C1, C2) causing cervical instability [8]. Large fontanels with delayed closure, short neck, and abnormal thoracic configuration have also been described. There may be frequent or spontaneous fractures, even from the neonatal age on [5].
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 two-step procedure for coupling development and usage of a pair of human neck models
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Y. W. Wang, L. Z. Wang, S. Y. Liu, Y. B. Fan
Geometrical model of the cervical spine was obtained based on CT images of a Chinese male (42 years old). The geometrical model contained the skull (C0), seven cervical vertebrae (C1–C7), one thoracic vertebra (T1), as well as intervertebral discs and facet joints between adjacent vertebrae. The skull, cervical vertebrae and thoracic vertebra were split in Mimics 10.0 (Materialise, USA). These hard tissues were then processed in Geomagic Studio 12.0 for reverse modelling (Geomagic, USA). Geometrical model of intervertebral discs were also built in Geomagic Studio 12.0. The linear distance between the C7/T1 joint and the head/neck joint (occipital condyles) was 125.4 mm in this geometrical model, compared to 118.8 mm reported by Robbins (1983) and 121.4 mm reported by Panzer and Cronin (2009), as shown in Figure 1. The thickness of the cortical bone and bony endplates were 0.5 and 0.6 mm, respectively (Panjabi et al. 2001). The finite element model was built using high quality mesh in ANSYS ICEM 13.0 (ANSYS, USA), and finally included totally 47813 nodes and 80538 elements (31492 hexahedral solid elements, 48960 quadrangular shell elements and 86 nonlinear spring elements) after convergent tests. Abaqus 12.0 (Dassault Systemes Simulia, France) was used to run this finite element model.
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.
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