preaortic

Preaortic is an anatomical term used to describe structures located anterior to the abdominal aorta. In common usage it denotes groups of lymph nodes, autonomic nerve plexuses, or fascial planes that lie on the ventral surface of the aorta within the retroperitoneal space. The term helps distinguish these anterior structures from those positioned lateral to the aorta (paraaortic) or posterior to it.

A primary example is the preaortic lymph nodes, which surround the origins of the major abdominal arteries: the celiac trunk, the superior mesenteric artery, and the inferior mesenteric artery. These nodes drain lymph from the foregut, midgut, and hindgut and typically funnel lymph toward the intestinal trunk, cisterna chyli, and eventually the thoracic duct.

Autonomic nervous system structures on the anterior surface of the aorta are often described as the preaortic plexuses, notably the celiac plexus (solar plexus) and the superior and inferior mesenteric plexuses. They provide sympathetic and parasympathetic innervation to abdominal viscera.

The term can also describe the pre-aortic or preaortic fasciae and spaces within the retroperitoneum, which lie between the peritoneum and the anterior surface of the aorta.

Clinically, a mass or inflammatory process in the preaortic space may involve lymph nodes, plexuses, or surrounding fascia and can have implications for staging of abdominal malignancies or presentation of retroperitoneal disease. In contrast, paraaortic refers to structures adjacent to the aorta but not strictly anterior.