The right and left triangular ligaments are peritoneal reflections connecting the posterior liver surface to the diaphragm. The right triangular ligament is a fold connecting the right lobe superior surface to the diaphragm; the left triangular ligament is a longer, more prominent fold connecting the left lobe to the diaphragm and the coronary ligament. Both are part of the coronary ligament complex that suspends the liver from the diaphragm.
Suspend the liver from the inferior diaphragm surface, preventing inferior descent of the liver and maintaining its position in the right upper quadrant.
The left triangular ligament is divided in major hepatic surgery (left hepatectomy, left lateral sectionectomy) and in laparoscopic procedures requiring mobilisation of the left lobe. It may be surprisingly thick and vascular in some patients, and its inadvertent division without haemostasis produces bleeding from diaphragmatic vessels. The right triangular ligament is divided in right hepatectomy and in mobilisation of the right lobe for retrohepatic IVC exposure. The falciform ligament is the anterior extension of the coronary ligament complex.
Dividing the left triangular ligament to mobilise the left liver lobe for left hepatectomy or oesophageal hiatus exposure may encounter variable hepatic venous tributaries within the ligament; energy device division with ligation of any substantial vessels prevents diaphragmatic bleeding.
