At what vertebral level does the transpyloric plane of Addison lie, and what structures cross it?

The transpyloric plane lies at the lower border of L1, midway between the jugular notch and pubic symphysis. It crosses the pylorus, neck of the pancreas, origin of the SMA, formation of the portal vein, duodenojejunal flexure, and the renal hila.

Clinical relevance. Surface planes localise deep organs to a body-wall landmark for examination and procedures.

More Detail

Transpyloric plane

The transpyloric plane is a horizontal reference plane at the lower border of the first lumbar vertebra (L1), found midway between the suprasternal notch and the pubic symphysis (about a hand's breadth below the xiphisternum).

Structures in the plane

• Pylorus of the stomach (hence the name)
• Neck of the pancreas
• Origin of the superior mesenteric artery; formation of the portal vein behind the pancreatic neck
• Duodenojejunal flexure
• Hila of both kidneys (right slightly lower), fundus of the gallbladder at the right ninth costal cartilage
• Termination of the spinal cord (conus medullaris) lies near this plane

Why it matters

Surface planes let you predict the organ underlying a sign or mass. The transpyloric plane localises the pancreas and pylorus, relevant to epigastric pain, masses, and surgical incisions.