The surgeon must first be aware of the anatomic differences of the two adrenal glands (see Plate 146, Figure 2). The left adrenal is in proximity to the aorta medially, the renal vein inferiorly, and the superior pole of the left kidney. It may be located near the renal hilum. Its main arterial supply comes directly from the aorta (12), but the main left adrenal vein (6) usually comes from the left renal vein (8). In contrast, the right adrenal is close to the superior pole of the kidney, the vena cava medially, and the right lobe of the liver superiorly. Its main arterial supply comes directly to its medial edge from the aorta (12), and the main right adrenal vein (5) comes directly from the inferior vena cava in a parallel manner. Both adrenal glands, however, have many arterial twigs from both the inferior phrenic arteries (9 and 10) and both renal arteries. Both adrenal glands are within gerota's fascia.