The inferior phrenic vein is a blood vessel that plays a specific role in the body’s circulatory system. These veins are generally associated with the diaphragm, the large muscle that separates the chest from the abdomen and is primarily responsible for breathing. As part of the venous network, they contribute to the return of deoxygenated blood towards the heart.
Where is the Inferior Phrenic Vein Located
The inferior phrenic veins originate on the inferior surface of the diaphragm, corresponding to the inferior phrenic arteries that supply this muscle. They are found in pairs, one on each side of the diaphragm. These vessels then follow a posterior course as they ascend.
The right inferior phrenic vein has a direct path, draining into the inferior vena cava (IVC) near where the IVC passes through the diaphragm. This occurs close to the right adrenal gland. Its course is adjacent to the right phrenic nerve and near the posterior surface of the liver.
The left inferior phrenic vein originates from the left diaphragm but has a more variable course. It is represented by two branches. One branch may drain into the left renal vein or the left suprarenal (adrenal) vein, while the other can pass in front of the esophageal hiatus of the diaphragm before opening into the inferior vena cava.
These veins are positioned in the upper abdominal cavity, near where the diaphragm meets abdominal organs. They are also close to the adrenal glands and the aorta. The left inferior phrenic vein may also receive tributaries from the lower esophagus.
What is the Inferior Phrenic Vein’s Role
The main function of the inferior phrenic vein is to collect deoxygenated blood from the diaphragm. This drainage removes metabolic waste products generated by the muscle’s constant activity during breathing, supporting the diaphragm’s function and performance.
Beyond the diaphragm, these veins also drain blood from the adrenal (suprarenal) glands. The suprarenal veins, particularly the left adrenal vein, empty into the left inferior phrenic vein. This connection shows the vein’s involvement in the venous drainage of upper abdominal structures.
The right adrenal vein, in contrast, drains directly into the inferior vena cava. The drainage from these hormone-producing glands is an additional contribution to the body’s overall circulation, ensuring deoxygenated blood and waste products return to the systemic circulation.
When the Inferior Phrenic Vein Matters Clinically
The inferior phrenic vein is clinically relevant due to its anatomical connections and drainage patterns. Its role as a potential collateral pathway is seen in conditions like portal hypertension. Here, increased pressure in the portal venous system can reroute blood, and the left inferior phrenic vein may form anastomoses (connections) with the portal venous system, potentially contributing to gastric varices.
Given its involvement in adrenal gland drainage, particularly on the left side, the inferior phrenic vein is significant in cases of adrenal tumors or hyperplasia. During adrenal venous sampling procedures, performed to diagnose and localize hormone-producing adrenal tumors, precise catheter placement is necessary. For the left adrenal vein, the catheter tip is positioned just beyond the opening of the left inferior phrenic vein to ensure accurate sampling of adrenal tributaries.
Furthermore, the inferior phrenic vein is a consideration during certain interventional radiology procedures. Embolization, a procedure to block blood vessels, may target branches of the inferior phrenic artery or its venous counterparts. This can be done to control bleeding from tumors or to reduce the blood supply to adrenal tumors as a palliative measure or to facilitate surgical removal.
Diagnostic imaging, such as CT scans and MRIs, can visualize the inferior phrenic veins. Radiologists and surgeons use these images to assess the vein’s anatomy, identify any anomalies, or observe its involvement in disease processes. Understanding its course and connections helps in planning surgical procedures involving the diaphragm or adjacent structures, minimizing the risk of complications like bleeding.