Learning Objective:

By the end of this article, learners should be able to identify the borders and contents of Calot’s triangle, recognize its anatomical variations, and understand its clinical significance in procedures like laparoscopic cholecystectomy.

Introduction

Calot’s triangle (or cystohepatic triangle) is a small anatomical space in the abdomen. It is located at the porta hepatis of the liver, where hepatic ducts and neurovascular structures enter or exit the liver.

Borders

The triangle is oriented so that its apex points toward the liver. Its borders are:

• Medial: common hepatic duct
• Inferior: cystic duct
• Superior: inferior surface of the liver

Note: The original description (1891) listed the cystic artery as the superior border. The modern definition is more consistent because the cystic artery has variable anatomy.

Activity

Contents

The contents of Calot’s triangle include:

• Right hepatic artery – a branch of the proper hepatic artery
• Cystic artery – usually arises from the right hepatic artery to supply the gallbladder
• Lymph node of Lund – the first lymph node of the gallbladder
• Lymphatics

Clinical Relevance

The triangle of Calot is crucial during laparoscopic cholecystectomy:

• Surgeons carefully dissect the triangle to identify its borders and contents, accounting for anatomical variations.
• Safe ligation of the cystic duct and cystic artery requires identification of the right hepatic artery.
• If the triangle cannot be delineated (e.g., severe inflammation), options include performing a subtotal cholecystectomy or converting to open surgery.

Activity