Abdominal Wall and Inguinal Canal Quiz

See Surface Regions and Wall Layers. Option D is correct: the four-quadrant map is made from a vertical median line, which runs down the midline of the body and separates right from left, and a horizontal transumbilical line through the umbilicus (the navel), which separates upper from lower. The two lines cross at the umbilicus and give the right upper, left upper, right lower and left lower quadrants. The names refer to the patient's own right and left, so a right upper quadrant is on the patient's right even when the patient is facing you. Clinicians use this quick map to describe where a patient has pain or a mass. The finer nine-region map adds more lines: two vertical midclavicular lines (dropped from the midpoint of each collarbone) and two horizontal planes make three columns and three rows, with names such as the epigastrium, umbilical region and hypogastrium. To remember the difference, picture a window frame for the quadrants (one up-and-down bar and one side-to-side bar crossing at the belly button) and a noughts-and-crosses grid for the nine regions (two lines each way).

• Four quadrants: A vertical median line and a horizontal transumbilical line cross at the umbilicus.
• Quadrant names: Right upper, left upper, right lower and left lower, using the patient's own right and left.
• Nine regions: These need two vertical midclavicular lines and two horizontal planes.

C lists the subcostal plane (just below the ribs) and the intertubercular plane (between the tops of the two hip bones). Both are horizontal planes of the nine-region map, and with no vertical line they cut the abdomen into bands, not quadrants. E lists the two midclavicular lines, which are parallel vertical lines, so on their own they give three strips. A pairs the linea alba, the fibrous seam in the midline of the abdominal wall, with the inguinal ligament, which runs along the groin. The linea alba is a sensible midline, but the ligament is a groin landmark and not a line across the umbilicus. B combines the two midclavicular lines with the transpyloric plane, a horizontal plane at about the level of the first lumbar vertebra rather than through the umbilicus, so it makes six areas instead of four quadrants.