Lumbar lymph nodes refer to a group of small organs that are part of the immune system. Lymph nodes are generally circular, bean-like organs that are dispersed throughout the body. The lumbar lymph nodes are located in the region of the body between the diaphragm (a muscle in the lower rib cage that helps with breathing) and pelvis, known as the lumbar region. They are also called the lateral aortic lymph nodes. The nodes are part of the lymphatic system of the human body.

They are situated alongside a vein in the torso known as the inferior vena cava and an artery known as the aorta. The common iliac nodes and lymphatic vessels found on the backside of the abdominal wall enter into the lumbar nodes.

The nodes also provide lymphatic vessel extensions that form lumbar trunks on both sides. The left lumbar trunk of the nodes receives drainage from the intestinal trunk. The lumbar trunks converge to become the thoracic duct.

The lumbar lymph nodes are responsible for draining body parts such as the lower limb, pelvic organs, the perineum (the area between the anus and the penis, in males, or vulva, in females), and the abdominal wall, among others.