Two vertical midclavicular lines and two horizontal planes give nine regions
Mnemonic
Two vertical, two horizontal lines, giving nine regions:
- Vertical: the two midclavicular lines
- Horizontal: the subcostal (or transpyloric) plane above and the transtubercular (or intertubercular) plane below
Reading across, top row: right hypochondrium, epigastrium, left hypochondrium; middle: right lumbar (flank), umbilical, left lumbar; bottom: right iliac (inguinal), hypogastrium (suprapubic), left iliac.
The transpyloric plane of Addison at L1, halfway between the jugular notch and the pubic symphysis, is the more useful landmark: it crosses the pylorus, the neck of the pancreas, the fundus of the gallbladder, the hila of both kidneys, the origin of the superior mesenteric artery and the end of the spinal cord.
Expansion
Top row - right hypochondrium, epigastrium, left hypochondrium
Middle row - right lumbar (flank), umbilical, left lumbar (flank)
Bottom row - right iliac fossa, hypogastrium (suprapubic), left iliac fossa
The dividing lines are:
- Two vertical mid-clavicular lines
- The subcostal plane (or transpyloric plane) above
- The intertubercular plane, joining the tubercles of the iliac crests, below
The nine-region scheme localises pain more precisely than four quadrants, and it maps onto embryology: foregut pain is epigastric, midgut pain is umbilical and hindgut pain is hypogastric.