The transpyloric plane, also known as Addison's plane, is an imaginary horizontal plane, located halfway between the suprasternal notch of the manubrium and the upper border of the symphysis pubis at the level of the first lumbar vertebrae, L1. It lies roughly a hand's breadth beneath the xiphisternum or midway between the xiphisternum and the umbilicus. The plane in most cases cuts through the pylorus of the stomach, the tips of the ninth costal cartilages and the lower border of the first lumbar vertebra.

Structures crossed

The transpyloric plane is clinically notable because it passes through several important abdominal structures. It also divides the supracolic and infracolic compartments, with the liver, spleen and gastric fundus above it and the small intestine and colon below it.

Lumbar vertebra and spinal cord

The first

lumbar vertebra The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse ...

lies at the level of the transpyloric plane. Despite the conus medullaris, the end of the spinal cord, being understood to terminate at the level of the transpyloric plane, there is significant variability. Up to 40% of people have spinal cords ending below the transpyloric plane.

Stomach

The transpyloric plane passes through the pylorus of the stomach, despite it being suspended by the lesser and greater omentum and being relatively mobile.Drake, Richard L.; Wayne, Vogl A.; Mitchell, Adam W.M. (2015).
Gray's Anatomy for Students
' (3rd ed.) Philadelphia: Churchill Livingstone Elsevier. p. 311.

Duodenum

The horizontal part of the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine ...

slopes upwards to the left of the vertical midline, following which the vertical ascending part of the duodenum reaches the transpyloric plane. It ends in the

duodenojejunal junction The duodenojejunal flexure or duodenojejunal junction is the border between the duodenum and the jejunum. Structure The ascending portion of the duodenum ascends on the left side of the aorta, as far as the level of the upper border of the seco ...

, which lies approximately 2.5 cm to the left of the midline and just below the transpyloric plane.

Pancreas

The

neck of pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an endocri ...

lies on the transpyloric plane, whilst the body and tail are to the left and above it.

Gallbladder

The fundus of the gallbladder projects from the liver’s inferior border at the intersection of the transpyloric plane and the right lateral midline.

Kidneys

Despite the right kidney lying 1 cm lower than the left (right just below and the left just above the plane), to be practical, the surface markings are taken the same way. The hilum of the kidney on the left and right is taken as 5 cm from the vertical midline and is on the transpyloric plane.

Vasculature

The superior mesenteric artery arises from the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

at the level of the transpyloric plane and emerges between the head and neck of the pancreas. The superior mesenteric vein is joined by the splenic vein to form the portal vein at the level of the transpyloric plane.

Spleen

The lower border of the spleen lies near the transpyloric plane.

Other structures

* the left and right colic flexure * the root of the transverse mesocolon. * cisterna chyli (which drains into the thoracic duct).

History

The transpyloric plane relates to the three-dimensional mapping of the abdomen founded on more than 10,000 measurements completed on 40 bodies, that surgeon

Viscount Addison Viscount Addison, of Stallingborough in the County of Lincoln, is a title in the Peerage of the United Kingdom. It was created on 6 July 1945 for the physician and politician Christopher Addison, 1st Baron Addison. He had already been created B ...

took at the turn of the 20th century.Addison, Sir Christopher, Viscount Addison of Stallingborough (1869 - 1951).
Royal College of Surgeons: Plarr's Lives of the Fellows Online. Retrieved 16 March 2018. Addison reported his findings in a paper titled, "On the anatomical topography of the abdominal viscera in man, especially the gastro-intestinal canal" in which he established a baseline for the anatomy of the abdomen based on the arrangement of the map of the Earth. Using the suprasternal notch as the North Pole of the trunk, and the upper border of the pubic symphysis as the South Pole, he drew a vertical line joining these two points as his

meridian Meridian or a meridian line (from Latin ''meridies'' via Old French ''meridiane'', meaning “midday”) may refer to Science * Meridian (astronomy), imaginary circle in a plane perpendicular to the planes of the celestial equator and horizon * ...

. At the meridian's midpoint, he then drew a perpendicular line corresponding to the

Equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can al ...

. As this transverse plane crossed the pylorus, he called it the transpyloric plane.

Images

File:Surface projections of the organs of the trunk.png, Surface projections of the organs of the

trunk Trunk may refer to: Biology * Trunk (anatomy), synonym for torso * Trunk (botany), a tree's central superstructure * Trunk of corpus callosum, in neuroanatomy * Elephant trunk, the proboscis of an elephant Computing * Trunk (software), in rev ...

, with transpyloric plane labeled at L1 File:Gray1034.png, Front view of the thoracic and abdominal viscera.
a. Median plane.
b. Lateral planes.
c. Trans tubercular plane.
d. Subcostal plane.
e. Transpyloric plane. File:Gray1227.png, Front of abdomen, showing surface markings for arteries and inguinal canal.

References

External links

Planes of the trunk
{{Authority control Anatomy