LUQ

The left upper quadrant (LUQ) is one of the four abdominal quadrants used in clinical assessment. It is delineated by a vertical line through the midline and a horizontal line through the umbilicus, separating the abdomen into left and right, and upper and lower regions. This quadrant is a common reference point in describing pain, tenderness, or injury.

Organs and structures typically located in the LUQ include the stomach, spleen, body and tail of the pancreas, portions of the left lobe of the liver, and the left kidney and adrenal gland. The splenic flexure of the colon and portions of the descending colon lie in this area, as do portions of the jejunum and ileum. The exact extent can vary among individuals.

Clinical significance of the LUQ arises in both diagnostic and traumatic contexts. Conditions affecting LUQ organs—such as splenomegaly, splenic injury, pancreatitis involving the tail of the pancreas, gastric ulcers, or splenic flexure issues—can produce localized pain in this region. Referred pain and certain signs, like Kehr sign (referred pain to the left shoulder from diaphragmatic irritation), may accompany LUQ pathology. Trauma to the left upper abdomen can injure the spleen or stomach and is a common cause of LUQ tenderness.

Imaging and evaluation often focus on LUQ structures when symptoms or exam findings localize there. Ultrasound or computed tomography (CT) can assess the spleen, stomach, pancreas, kidneys, and adjacent bowel segments to aid diagnosis. The LUQ designation remains a practical reference in medical documentation and imaging reports.