The zona reticularis produces androgens and plays a role in the development of secondary sexual characteristics. The adrenal cortex is much larger than the smaller medulla, which only accounts for approximately 15% of the gland. The adrenal medulla is more of a reddish-brown color. A thick capsule consisting of connective tissue surrounds the entire adrenal gland. The adrenal cortex tends to be fattier and thus has a more yellow hue. The adrenal gland is composed of two distinct tissues: the outer cortex and the inner medulla. The left adrenal gland sits medially to the spleen, superior to the splenic artery and vein, lateral to the abdominal aorta, and anterior to the diaphragm. The right adrenal gland sits just below the liver, posterior to the inferior vena cava, and anterior to the diaphragm. Each gland measures 50 mm in height, 30 mm in breadth, and 10 mm in thickness. At birth, the adrenal glands are roughly one-third the size of the kidney, though, by adulthood, they are only one-thirtieth the size of the kidney. Each adrenal gland is found in the epigastrium at the top of the kidney opposite the 11th intercostal end of the vertebral space and the 12th rib. The right suprarenal gland is pyramidal in form, while the left suprarenal gland is crescentic in shape. They are enclosed within the superior renal fascia and sit in the perirenal space.

Both adrenal glands rest on top of the kidneys on their respective side of the body. The adrenal glands lie close to critical vessels and organs.

Medulla of adrenal gland