The falciform ligament is a sickle-shaped fold of peritoneum, a membrane lining the abdominal cavity. It attaches the liver to the anterior abdominal wall and the diaphragm.
Anatomy and Location
The falciform ligament is a double-layered extension of the parietal peritoneum. It extends obliquely from the front to the back of the abdomen, attaching to the anterior abdominal wall from the diaphragm down to the umbilicus. One surface contacts the peritoneum behind the right rectus abdominis muscle and the diaphragm, while the other touches the left lobe of the liver.
Its free, inferior border encloses the ligamentum teres hepatis, also known as the round ligament of the liver, along with paraumbilical veins. The ligamentum teres is a fibrous cord that connects the liver to the umbilicus. The falciform ligament also plays a role in dividing the subphrenic spaces within the abdomen into right and left compartments.
Developmental Role and Adult Significance
The falciform ligament originates from the embryonic ventral mesentery. During embryonic development, the umbilical vein passes between the two layers of this developing ligament, carrying oxygenated blood from the placenta to the fetal liver. This vein courses through the ventral mesogastrium to reach the developing inferior vena cava.
After birth, the umbilical vein gradually obliterates and transforms into a fibrous cord known as the ligamentum teres hepatis. This transformation makes the falciform ligament largely vestigial in terms of active function in adults. In adults, its primary significance is as an anatomical landmark. It serves to divide the liver into anatomical right and left lobes on its anterior surface.
Associated Clinical Conditions
Despite its limited functional role in adults, the falciform ligament can become clinically relevant. In cases of portal hypertension, a condition involving increased pressure in the portal vein system, the paraumbilical veins within the falciform ligament can enlarge and become prominent. This can lead to a visible network of engorged veins around the umbilicus, a sign referred to as caput medusae. While traditionally thought to be a recanalized umbilical vein, research suggests it is actually the enlargement of these paraumbilical veins.
The falciform ligament also holds importance during liver trauma or surgical procedures. It acts as a landmark for surgical approaches, helping surgeons navigate the upper abdomen. In rare instances, the falciform ligament can be the site of cysts or hernias. Falciform ligament cysts are uncommon, but can cause symptoms such as abdominal pain or a palpable mass.
Hernias through the falciform ligament are also rare, occurring when abdominal contents protrude through an abnormal opening in the ligament. These hernias can be congenital or, increasingly, iatrogenic, often linked to prior laparoscopic surgeries. Such hernias can result in acute abdominal pain and symptoms suggestive of intestinal obstruction. The falciform ligament’s close anatomical association with the liver also means that infections or malignancies from adjacent structures can sometimes spread to it.