To facilitate clinical description, the general topography of the abdomen is divided into four quadrants or nine regions by lines on the surface of the anterior abdominal wall. The four quadrants are created by vertical and horizontal lines passing through the umbilicus, whereas the nine regions are delineated by two vertical and two horizontal lines.
- midclavicular lines - two vertical lines are the midclavicular lines which extend to the midinguinal point
- intertubercular plane - a lower transverse line drawn between the tubercles of the iliac crest
- transpyloric plane - an upper transverse line which lies midway between the suprasternal notch and superior surface of the symphysis pubis (or between the xiphisternum and umbilicus.
Using the four lines, the three central regions created between them, from above down are:
Similarly, the lateral regions from above down are: