The suprarenal plexus is formed by branches from the celiac plexus

Celiac plexus

The celiac plexus or coeliac plexus, also known as the solar plexus, is a complex network of nerves located in the abdomen, where the celiac trunk, superior mesenteric artery, and renal arteries branch from the abdominal aorta...

, from the celiac ganglion, and from the phrenic and greater splanchnic nerves, a ganglion

Ganglion

In anatomy, a ganglion is a biological tissue mass, most commonly a mass of nerve cell bodies. Cells found in a ganglion are called ganglion cells, though this term is also sometimes used to refer specifically to retinal ganglion cells....

 being formed at the point of junction with the latter nerve.

The plexus supplies the suprarenal gland, being distributed chiefly to its medullary

Adrenal medulla

The adrenal medulla is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine , norepinephrine , and a small amount of dopamine in response to...

portion; its branches are remarkable for their large size in comparison with that of the organ they supply.