[TA] the most substantial, superior portion of the abdominal aortic plexus lying anterior to the aorta at the level of origin of the celiac trunk (vertebral level T-12); the celiac ganglia lie within the plexus; it is formed by contributions from the greater splanchnic and vagus (especially the posterior or right vagus) nerves and communicating branches to and from the superior mesenteric and renal plexuses and ganglia; most sympathetic, parasympathetic and visceral afferent fibers serving the abdominal viscera pass through this plexus. SYN: plexus coeliacus [TA], plexus (nervosus) celiacus [TA], solar plexus.