This structure comprises the space and content within the boundaries of the abdominal proper cavity but excludes the walls that define and enclose the space. Previously SNOMED CT used the word 'compartment' to describe structures comprising the cavity and content but FMA has used the same word to include cavity, content and wall. As a consequence, the preferred notation is intra-abdominopelvic proper structure as this more clearly excludes the 'wall' structures. The intra-abdominopelvic proper structure is bounded by, but excludes the following 'wall' structures: superiorly the thoracic diaphragm; inferiorly the superior pelvic aperture; anteriorly the anterior abdominal (including the lateral abdominal wall); and posteriorly the posterior wall of abdomen proper. Note, the structures that form the boundaries are excluded.