NCIt definition : Any portion of the body that lies within the boundary, either internally or externally,
of the abdomen: superior margin, the thorax; inferior margin the pelvis; lateral margins,
the ribs.;
Alternative definition : CDISC: Any portion of the body that lies within the boundary, either internally or
externally, of the abdomen: superior margin, the thorax; inferior margin, the pelvis;
lateral margins, the ribs.;