Finite Element Modelling of the Healthy Wrist Joint - Computational Biomechanics of the Wrist Joint - page 33

Chapter 4
Finite Element Modelling of the Healthy
Wrist Joint
Abstract The finite element method was used to perform contact analysis in the
wrist joint, thus requires its model construction preceding any analyses. The steps
and procedures are as explained in this chapter. The three-dimensional model of
the healthy wrist was constructed from the CT images of a healthy volunteer.
Segmentations were performed on CT images selecting the regions of the cortical
and the cancellous bone. The completed three-dimensional model was then con-
structed consisting of solid linear first order tetrahedral elements. As no soft tissues
appeared in CT images, manual constructions of it were performed. The articular
cartilages were modelled by extruding the articulating surfaces with a thickness
size half of the minimum distance between the two bones. Set of links were used to
simulate the ligamentous structure. The model was then compared with anatomical
software for precision, assuring its reliability for future consumption.
Keywords Healthy wrist Finite element model Simulation of the ligament
Simulation of the cartilage Conversion from 2D images to 3D model
4.1 Bone Model Reconstruction
A three-dimensional (3D) model of the healthy wrist joint was reconstructed from
computed tomography (CT) images of a healthy asymptomatic male, 53 years old
volunteer with no radiological signs of pathology. The scans were taken from the
whole upper limb of a healthy human body in extended (33.11 o ) and deviated
(17.34 o ulnar) wrist positions, measured relative to anatomically based radial
coordinate system [ 1 ]. The radiograph images of the wrist, ranging from the distal
end of the long bones of the left forearm—radius and ulna- to the proximal third of
the metacarpals were then cropped. The total length of the scans was 102.3 mm