The human torso is mapped into specific territories to help medical professionals accurately communicate about the location of internal organs or symptoms. While the abdomen is sometimes divided into four general quadrants, a more detailed nine-region system is used for greater precision. This anatomical grid provides a standardized language for discussing where various organs lie beneath the surface, allowing for the exact placement of areas like the umbilical region, which is centered around the navel.
Defining the Nine Abdominal Regions
The nine-region system divides the anterior abdominal wall using four imaginary planes, creating a three-by-three grid. This method offers a more localized view of the internal anatomy compared to the simple four-quadrant division. Two vertical and two horizontal lines establish the boundaries of the nine regions.
The two vertical lines are the mid-clavicular lines, projected downward from the midpoint of each collarbone. These lines run parallel and mark the lateral boundaries of the central three regions.
The horizontal divisions are the upper transpyloric plane and the lower intertubercular plane. The transpyloric plane is positioned roughly halfway between the jugular notch and the pubic symphysis. The intertubercular plane connects the tubercles on the upper part of the hip bones. These four intersecting lines carve the abdomen into three upper, three middle, and three lower compartments.
Precise Boundaries of the Umbilical Region
The umbilical region is situated in the center of the nine-region grid, surrounding the navel (umbilicus). It occupies the middle section of the central column. Its boundaries are defined by the imaginary lines established in the mapping system.
The vertical borders are the two mid-clavicular lines, placing it squarely in the midline of the body. Superiorly, the transpyloric plane separates it from the epigastric region. Inferiorly, the intertubercular plane marks its lower boundary, separating it from the hypogastric region.
This central location means the umbilical region is surrounded by eight other areas. The two lumbar regions flank it on the right and left sides. The four remaining corners touch the hypochondriac and iliac (inguinal) regions.
Primary Organs Located Within
The umbilical region contains several major abdominal structures, including the navel itself. The majority of the small intestine, specifically portions of the jejunum and ileum, are coiled within this central area. These mobile segments of the small bowel fill much of the peritoneal space deep to the umbilical region.
A portion of the large intestine, the transverse colon, also traverses this area as it crosses the abdomen. This region is also an important landmark for major blood vessels. The abdominal aorta and the inferior vena cava, which are retroperitoneal structures, lie behind the intestines.
The umbilical area often contains the inferior poles of both the left and right kidneys. Although the head of the pancreas is mostly in the adjacent epigastric region, parts of the duodenum can extend into the umbilical area.