Ligamentum Venosum

Overview

The ligamentum venosum is a fibrous remnant of the fetal ductus venosus, a vascular shunt that once allowed oxygenated blood from the placenta to bypass the fetal liver. After birth, the ductus venosus closes and becomes the ligamentum venosum. Though non-functional in adults, it is an important anatomical landmark within the liver and is closely associated with the hepatic vasculature.

Location

The ligamentum venosum is located in the posterior part of the liver, specifically:

• Within the fissure between the left lobe and the caudate lobe of the liver

• Runs from the left branch of the portal vein at the porta hepatis upward to the inferior vena cava (IVC)

• Occupies the ligamentum venosum fissure on the visceral surface of the liver

It is deep to the peritoneum and part of the division between functional lobes of the liver based on Couinaud’s classification.

Structure

The ligamentum venosum is a:

• Fibrous cord approximately 3–5 cm in length in adults

• Vestigial structure: It is the obliterated ductus venosus, composed of dense connective tissue

• Non-patent: It is non-functional after birth and contains no active blood flow

It lies anterior to the caudate lobe and posterior to the left hepatic vein and left lobe of the liver.

Function

In adults, the ligamentum venosum has no functional role, as it is a fibrous remnant. However, in fetal life, its precursor—the ductus venosus—had a vital circulatory function:

• Bypassed hepatic circulation: Allowed oxygen-rich blood from the umbilical vein to flow directly into the inferior vena cava, bypassing the liver

• Maintained oxygen delivery: Helped shunt blood toward the heart and brain during fetal development

Physiological Role(s)

While physiologically inactive in adults, the ligamentum venosum has secondary roles:

• Surgical and anatomical landmark: Helps demarcate the separation between the left and caudate lobes of the liver

• Reference in Couinaud's classification: Marks the left boundary of segment I (caudate lobe) and aids in liver segmental resections

• Structural support: May provide minimal anchoring of adjacent hepatic tissue or vasculature due to its fibrous nature

Clinical Significance

The ligamentum venosum holds significance in various clinical and surgical contexts:

• Liver segmentation: A key landmark in imaging and hepatic surgeries, especially in anatomical liver resection

• Radiological landmark: Visualized on CT or MRI to help identify caudate lobe, left hepatic vein, and fissural anatomy

• Persistent ductus venosus (rare): In neonates, failure of the ductus venosus to close can lead to abnormal shunting and hepatic dysfunction

• Transplantation planning: Used to distinguish left and right lobes and guide hepatic artery and portal vein dissection

• Portal hypertension diagnostics: May serve as a reference point in imaging when evaluating abnormal collateral circulation or varices

While the ligamentum venosum itself does not cause disease, its location and historical function make it relevant in hepatobiliary imaging, embryology, and surgical anatomy.