Accessing 3D Location of Standing Pelvis: Relative Position of Sacral Plateau and Acetabular Cavities versus Pelvis

Figure 5

Examples of shapes and orientations of standing pelvis. Parameters describe. (i) 3D pelvic orientation (𝜓_𝑝,𝜃_𝑝,𝜙_𝑝) (ii) The relative position of articular surfaces versus pelvis: flexion 𝛼_𝑠 and lateral flexion 𝛽_𝑠 of the sacral plateau, couples of angles (𝛼_𝑎,𝛽_𝑎) (𝛼_𝑎′,𝛽_𝑎′) orienting the axis of each acetabular cavity. (iii) The indices of pelvic asymmetry: linear offset ysp of the sacral plateau center, and offset 𝐾_𝑎𝐾_𝑎′ between cavity axes at level of the pelvic plane of symmetry.