Round Ligament of Liver

Overview

The round ligament of the liver, also known as the ligamentum teres hepatis, is a fibrous remnant of the fetal umbilical vein. It no longer conducts blood in postnatal life but remains a significant anatomical landmark on the inferior surface of the liver. It is enclosed within the lower free margin of the falciform ligament and connects the liver to the anterior abdominal wall.

Location

The round ligament is located on the anterior and inferior aspect of the liver. Specifically, it:

• Lies within the inferior free margin of the falciform ligament

• Extends from the umbilicus to the inferior surface of the liver

• Travels in the fissure between the left lobe and quadrate lobe of the liver

• Terminates at the left branch of the portal vein near the porta hepatis

Structure

The round ligament is a fibrous cord, typically 3–5 mm in diameter. Its features include:

• Embryological origin: It is the obliterated left umbilical vein, which carried oxygenated blood from the placenta to the fetus

• Contained within: The falciform ligament, a double layer of peritoneum that attaches the liver to the anterior abdominal wall

• Covered by peritoneum: It is externally enveloped by a serosal layer

Though nonfunctional after birth, the ligament can become a conduit for collateral veins in certain pathological conditions.

Function

In fetal life, the structure that becomes the round ligament performs a vital circulatory function:

• Fetal role: The umbilical vein carries oxygen-rich blood from the placenta to the fetus, entering the liver and bypassing via the ductus venosus

After birth, the round ligament has no active physiological function but retains structural and surgical importance.

Physiological Role(s)

While inactive postnatally, the round ligament has secondary physiological and clinical roles:

• Landmark for segmentation: Marks the boundary between the left medial and left lateral segments of the liver (Couinaud’s segments III and IV)

• Collateral pathway in portal hypertension: May recanalize and form paraumbilical veins, leading to caput medusae

• Guide in surgical and imaging procedures: Aids in navigation during laparoscopic surgery and hepatic resections

Clinical Significance

The round ligament may be involved or used in various clinical scenarios:

• Portal hypertension: In conditions such as liver cirrhosis, the ligament may reopen, allowing paraumbilical veins to dilate and cause visible abdominal wall varices (caput medusae)

• Surgical landmark: Used in hepatic surgery to identify liver segments or locate the porta hepatis

• Liver transplantation: The round ligament may be used as a reference or anchoring structure during graft implantation

• Laparoscopic access: The falciform and round ligaments are sometimes divided to enhance access to upper abdominal organs

• Recanalization: Though usually fibrotic, it may regain patency in severe portal hypertension, serving as a spontaneous shunt

While small and functionless after birth, the round ligament of the liver serves as an important anatomical and surgical landmark and may become pathologically relevant in liver disease.