Topographically, the abdomen can be divided into right and left upper and right and left lower quadrants by vertical and horizontal lines through the umbilicus.

The abdomen may also be divided into nine regions by two longitudinal lines (right and left midclavicular lines) and two transverse planes (subcostal and intertubercular planes). The regions are: right and left hypochondriac, right and left lumbar, right and left inguinal (or iliac), epigastric, umbilical and hypogastric.