The human abdomen is the section of the body between the chest and the pelvis. This area houses many organs involved in vital bodily functions, such as digestion, waste filtration, and hormone production. To understand the location of these structures, the abdomen is often divided into specific regions.
Organs Primarily on the Left Side
Several major organs are predominantly located within the left side of the abdomen. The spleen, a fist-sized organ, is in the upper left abdomen, nestled beneath the rib cage and above the stomach. It filters blood, removing old or damaged red blood cells and producing white blood cells that help fight infection.
The stomach, a J-shaped muscular organ, sits in the upper abdomen, largely on the left side. It plays a primary role in digestion by mixing food with acids and enzymes before passing it to the small intestine.
The pancreas, an elongated gland, lies horizontally across the upper abdomen, behind the stomach. Its tail extends distinctly into the left side, close to the spleen. This organ produces digestive enzymes and hormones that regulate blood sugar.
The left kidney, one of a pair, is on the left side of the abdomen, below the rib cage and near the spine. It filters waste products and excess fluid from the blood to produce urine.
Further down, the descending colon is a section of the large intestine on the left side of the abdomen, extending downwards from beneath the spleen. It stores solidified stool and absorbs water before the waste moves towards the rectum.
Following the descending colon, the sigmoid colon, an S-shaped segment of the large intestine, is in the lower left abdomen and often extends into the pelvis. It transports and stores fecal matter, absorbing some water and nutrients, before elimination.
Organs Extending into the Left Abdomen
Some organs are not exclusively situated on the left side but have portions or significant presence that extend into this region. The small intestine, a long, coiled tube approximately 5.5 meters (18 feet) in length, occupies a large portion of the abdominal cavity. Specifically, the jejunum, which is the middle section of the small intestine, and the ileum, its final segment, often have loops that extend into the left upper and central abdomen. These sections are responsible for the absorption of nutrients from digested food.
The left adrenal gland is positioned directly atop the left kidney. These glands produce hormones that regulate various bodily functions, including metabolism and stress response.
The lower esophagus, the tube that carries food from the mouth to the stomach, enters the upper left abdomen as it connects to the stomach.
The diaphragm, the dome-shaped muscle separating the chest from the abdomen, forms the superior boundary of the abdominal cavity. A portion extends over the stomach and spleen in the upper left region.
Understanding Abdominal Regions
Healthcare professionals use anatomical mapping systems to pinpoint organ locations within the abdomen. One common method divides the abdomen into four quadrants using imaginary vertical and horizontal lines intersecting at the navel: the left upper quadrant (LUQ), left lower quadrant (LLQ), right upper quadrant (RUQ), and right lower quadrant (RLQ).
A more detailed system divides the abdomen into nine regions using two vertical and two horizontal lines. The left side of this grid includes the left hypochondriac (upper left), left lumbar (middle left), and left iliac (lower left) regions. This regional mapping provides a precise framework for describing organ placement.