Relations

The right adrenal lies between the liver and the vena cava. The left adrenal lies close to the aorta and is covered on its lower surface by the pancreas. The spleen lies superior and lateral to it.

Arterial

Each adrenal is supplied by three sets of arteries: the superior adrenal (from the inferior phrenic artery), the middle adrenal (from the aorta), and the inferior adrenal (from the renal artery). These vessels branch into as many as 50 arterioles.

 Three arteries usually supply each adrenal gland:[7]

• The superior suprarenal artery, a branch of the inferior phrenic artery
• The middle suprarenal artery, a direct branch of the abdominal aorta
• The inferior suprarenal artery, a branch of the renal artery

These blood vessels supply a network of small arteries within the capsule of the adrenal glands. Thin strands of the capsule enter the glands, carrying blood to them.[7]

Venous blood is drained from the glands by the suprarenal veins, usually one for each gland:[7]

 

 

• The right suprarenal vein drains into the inferior vena cava
• The left suprarenal vein drains into the left renal vein or the left inferior phrenic vein.

The central adrenomedullary vein, in the adrenal medulla, is an unusual type of blood vessel. Its structure is different from the other veins in that the smooth muscle in its tunica media (the middle layer of the vessel) is arranged in conspicuous, longitudinally oriented bundles.[2]

Variability[edit]

The adrenal glands may not develop at all, or may be fused in the midline behind the aorta.[10] These are associated with other congenital abnormalities, such as failure of the kidneys to develop, or fused kidneys.[10] The gland may develop with a partial or complete absence of the cortex, or may develop in an unusual location.[10]

 

Blood supply to the adrenal glands is derived from the superior, middle, and inferior suprarenal arteries. Branches of these arteries form a capillary network arranged so that blood flows from the outer cortex toward the center area, following a radially oriented sinusoid system. This direction of blood flow controls the access of steroid hormones to the circulation and concentrates the steroid hormones at the core of the adrenals, thus modulating the activities of enzymes involved in catecholamine synthesis.

 

Venous

Blood from the right adrenal is drained by a very short vein into the vena cava; the left adrenal vein terminates in the left renal vein.

Location and blood supply of the adrenal glands (schematic).

(Reproduced, with permission, from Miller WL, Tyrrell JB. The adrenal cortex. In: Felig P, et al, eds. Endocrinology and Metabolism. 4th ed. McGraw-Hill; 2002.)

 

Lymphatics

The lymphatic vessels accompany the suprarenal vein and drain into the lumbar lymph nodes.