This segment relates to the volume of the trunk that is bounded by and includes: superiorly thoracic diaphragm and inferiorly the perineum and external genitalia. The volume includes the entire transverse thickness of the body over the longitudinal extent between these upper (superior) and lower (inferior) boundaries including the overlying muscles, skin and subcutaneous tissue. The segment includes the abdominopelvic cavity, contents and wall including the posterior lumbar region, the volume of the true and false pelvic cavities including the bony pelvis and pelvic wall, the entire perineum and external genitalia including skin and subcutaneous tissue.