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

<table>Illustrating the method for locating frames affixed to sacral plateau from biplanar radiography coupled with geometric modelling. The sacral plateau is modelled as a plane bounded by an elliptic brim. Parts of brim projections are shaped as real and flattened ellipses. Sacral plateau center and normal vector projections are identified on each projected brim. Brim center <svg height="15.6875" id="M26" style="vertical-align:-3.39066pt" version="1.1" viewbox="0 0 18.262501 15.6875" width="18.262501" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.4)"><use xlink:href="#x1D442"></use></g>
<g transform="matrix(.012,-0,0,-.012,13.113,15.475)"><use xlink:href="#x1D460"></use></g>
</svg> and normal vector <svg height="11.9625" id="M27" style="vertical-align:-3.39066pt" version="1.1" viewbox="0 0 13.7375 11.9625" width="13.7375" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,7.675)"><path d="M495 86q-46 -47 -87 -72.5t-63 -25.5q-43 0 -16 107l49 210q7 34 8 50.5t-3 21t-13 4.5q-35 0 -109.5 -72.5t-115.5 -140.5q-21 -75 -38 -159q-50 -10 -76 -21l-6 8l84 340q8 35 -4 35q-17 0 -67 -46l-15 26q44 44 85.5 70.5t64.5 26.5q35 0 10 -103l-24 -98h2
q42 56 97 103.5t96 71.5q46 26 74 26q9 0 16 -2.5t14 -11.5t9.5 -24.5t-1 -44t-13.5 -68.5q-30 -117 -47 -200q-4 -19 -3.5 -25t6.5 -6q21 0 70 48z" id="x1D45B"></path></g>
<g transform="matrix(.012,-0,0,-.012,8.6,11.762)"><use xlink:href="#x1D460"></use></g>
</svg> are 3D located from using photogrammetric techniques.</table>

Radiology Research and Practice

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Figure 2

Figure 2: Accessing 3D Location of Standing Pelvis: Relative Position of Sacral Plateau and Acetabular Cavities versus Pelvis 