Finite element models are increasingly important in understanding @entity542 mechanisms and designing new injury prevention equipment. Although boundary conditions strongly influence model responses, only limited quantitative data are available. While experimental studies revealed some motion between brain and skull, little data exists regarding the base of the skull. Using magnetic resonance images (MRI) of the caudal brain regions, we measured in vivo, quasi-static angular displacement of the cerebellum (CB) and @entity3308 ( @entity3308 ) relative to skull, and axial displacement of @entity3308 at the foramen magnum in supine @entity1 subjects (N=5). Images were obtained in flexion (7 degrees - 54 degrees ) and neutral postures using SPAMM tagging technique (N=47 pairs). Rigid body skull rotation angle from neutral posture (theta, degrees) was determined by extracting the edge feature points of the skull, and rotating and displacing the coordinates in one image until they matched those in the other. Tissue rotation was obtained by comparing tag lines in image pairs before and after flexion, and the motion of @entity3308 and CB were expressed relative to skull rotation and displacement. During flexion, the CB rotated in the flexion direction, exceeding the skull rotation, but relative @entity3308 rotations were negligible. Meanwhile, the @entity3308 moved caudally toward the foramen magnum. With a flexion angle of 54 degrees , the 95% confidence interval for the relative @entity717 was 2.7 degrees - 4.3 degrees , and 0.8 - 1.6mm for the relative @entity3308 axial displacement. Albeit quasi-static, this study provides important data that can be implemented to create more life-like boundary conditions in @entity1 finite element models.

In vivo measurements of XXXX brain displacement.

@entity1 :: ('9606', 'Species') :: ['human'] @entity717 :: ('MESH:D009069', 'Disease') :: ['CB rotation'] @entity542 :: ('MESH:D006259', 'Disease') :: ['head injury'] @entity3308 :: ('MESH:D020295', 'Disease') :: ['BS', 'brainstem']
@entity1 :: (9606,Species) :: ['human']
