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Designing for Head and Neck Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The interior of the skull is more detailed and intricate then just one hollow space. The skull has several hollow areas, each with a specific function. Major superficial skull cavities are the eye sockets or orbits, ear canals, oral (mouth) cavity, and nasal (nose) cavity. The inside of the cranium is shaped around these cavities. The largest internal hollow area, the cranial cavity, acts as a container that holds the brain along with the CSF. The sinuses are hollow cavities near the respiratory passages and the cranial cavity. The spinal cord passes through a large opening at the base of the skull, the foramen magnum. These details are also seen in Figure 3.2. Additional small openings or passages throughout the skull provide spaces for nerves and blood vessels as they connect from inside the head to the superficial structures of the head.
Investigation of dynamic deformation of the midbrain in rear-end collision using human brain FE model
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Noritoshi Atsumi, Masami Iwamoto, Yuko Nakahira, Yoshitaka Asano, Jun Shinoda
Increases in the MPS values observed in the bottom region of the cerebellum and in the transition region from the medulla to the spinal cord for a rear-end collision at 46 km/h (Figure 6C-b/c) could be caused by the structural instability around the foramen magnum. These regions can experience an inertial force resulting in large deformations from not enough support from the cranial bone, especially in a rear-end crash scenario with a high impact velocity associated with larger posterior flexion of the head. To confirm the lower influence of the boundary condition at the foramen magnum on the strain values in the midbrain, we conducted an additional simulation of a rear-end collision at 46 km/h, in which the nodes of the bottom of cerebellum and the brain stem at the level of the foramen magnum were constrained to the cranial bone (Figure 8A). As shown in Figures 8B and 8C, it was confirmed that higher MPS values occurred in the midbrain regardless of the boundary conditions around the foramen magnum.
The cushioning function of woodpecker’s jaw apparatus during the pecking process
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Peng Xu, Yikun Ni, Shan Lu, Sijian Liu, Xue Zhou, Yubo Fan
Different loading conditions of BI, BIQJ and FI models are shown in Figure 1(a,b). A ball weighing 40 g and with a diameter of 20.14 mm was used to hit GSW’s head directly in BI, BIQJ and FI simulations. As for boundary conditions, the degrees of freedom of elements around the foramen magnum (an oval opening at the base of the skull) were all fixed except the rotational DOF in the sagittal plane.
Mechanisms of cervical spine injury and coupling response with initial head rotated posture – implications for AIS coding
Published in Traffic Injury Prevention, 2022
Narayan Yoganandan, Jamie Baisden, John Humm, Vicky Varghese
Five PMHS specimens were obtained after obtaining approvals from the Institutional Review Boards. The specimens were prescreened for the Human Immunodeficiency Virus, and Hepatitis B and C. All specimens were considered normal for the age and had no prior surgical interventions to the head and spine. Pretest radiographs of the head-neck complex were obtained, and bone densities were determined using the quantitated computed tomography images. Measurements were made of the atlas at its anterior and posterior tubercles, bilateral anterior and medial lateral mass, and bilateral posterior arches. The contents of the cranium were removed after sectioning the structure rostral to the base of the skull, and the integrity of the occipital condylar structures to the subaxial spinal column was maintained. The caudal end of the specimen was embedded in polymethyl-methacrylate while ensuring the unconstrained condition to the cervico-thoracic disk, and the superior end of the fixation was parallel to the transverse plane, i.e., along the laboratory x-y plane. An interface plate was attached to the top of the skull base and centered rostrally to the foramen magnum. A six-axis load cell (Sunrise Instruments, Nanning, China) was fixed to the interface plate to measure the occipital condyle forces and moments, and another six-axis load cell was attached to thoracic end. The external loading was applied using a custom angular displacement test device that converted the linear motion of a vertically aligned electro-hydraulic piston to a torque about the occipital condyle joint (Humm et al. 2021). The operational details of the device are provided in the cited publication and not described here due to word constraints. The inferior load cell was fixed to the top of a six-degree-of-freedom spinal positioning apparatus to orient the posture of the specimen such that the occipital condyle joint was aligned with the torque axis of the angular displacement device. The head was angulated by 30 degrees simulating left axial rotation, and the sagittal orientation of the first thoracic vertebra was aligned at 25 degrees with respect to the transverse plane. After preconditioning, the initial/pre-head rotated head-neck specimen was loaded under the left lateral bending mode at a velocity of 1.5 m/s and limited to 50 degrees. Peak forces and bending moments in all the three anatomical planes at the occipital condyles are reported in the results section. After the test, x-rays were obtained, and CT scanning was done. Injuries to the spine were identified by a practicing neurosurgeon, and they were scored using the Abbreviated Injury Scale, AIS 2015 version (AIS 2015).