Suprarenal Veins

The suprarenal veins are the primary venous drainage pathways of the adrenal (suprarenal) glands. Each adrenal gland is drained by a single, large suprarenal vein that collects blood from the rich subcapsular plexus formed by the numerous suprarenal arteries. These veins are clinically significant due to their asymmetric drainage patterns and close anatomical relationships to major vessels such as the inferior vena cava and renal vein.

Venous Drainage Pattern

Course and Anatomical Relations

Right Suprarenal Vein:

• Very short and thin (~1–2 cm), enters the inferior vena cava directly on its posterolateral surface
• Closely associated with the right lobe of the liver and the inferior phrenic vein
• Often encountered during right adrenalectomy, requiring delicate handling to prevent hemorrhage

Left Suprarenal Vein:

• Longer than the right, drains into the superior aspect of the left renal vein
• Often joins with the left inferior phrenic vein before entering the renal vein
• Passes posterior to the pancreas and splenic vein

Drainage Dynamics

• Venous blood from the adrenal cortex and medulla flows into central medullary venules
• These venules converge into a single central suprarenal vein
• This vein exits the gland at the hilum and follows the pattern described above (right → IVC, left → renal vein)
• Medullary blood is enriched with cortisol due to cortical flow; this enhances epinephrine synthesis via PNMT activity

Clinical Significance

Adrenal Surgery

• Control of the suprarenal vein is a critical step in adrenalectomy
• The right vein must be clipped early due to its short, fragile nature and direct drainage into the IVC
• Left-sided procedures offer more length and easier access due to drainage via the renal vein

Pheochromocytoma Management

• Adrenal medullary tumors can release massive surges of catecholamines during surgical handling
• Early ligation of the suprarenal vein minimizes systemic hormone spill during tumor mobilization

Thrombosis and Compression

• Renal vein thrombosis or compression (e.g., by tumors or retroperitoneal masses) can impair left adrenal drainage
• May lead to adrenal congestion or rarely adrenal hemorrhage

Imaging and Intervention

• Suprarenal veins can be visualized on contrast-enhanced CT or MR venography
• Important in planning adrenal vein sampling — a diagnostic procedure for distinguishing causes of primary aldosteronism

Anatomical Variations

• Accessory suprarenal veins may drain into the gonadal vein, inferior phrenic vein, or lumbar veins
• Double suprarenal veins may exist on one or both sides
• Fusion with nearby venous tributaries may obscure typical surgical anatomy