In anatomy, the epigastrium (or epigastric region) is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane.The epigastrium is one of the nine regions of the abdomen, along with the right and left hypochondria, right and left lateral regions (lumbar areas or flanks), right and left inguinal regions (or fossae), and the umbilical and pubic regions.uring breathing the diaphragm contracts and flattens, displacing the viscera and producing an outward movement of the upper abdominal wall (epigastric region). It is a convergence of the diaphragm and the abdominals, so that when both sets of muscles (diaphragm and abdominals) tense, the epigastrium pushes forward.