M01.06.002 Calot’s Triangle

Calot’s triangle, also known as the cystohepatic triangle, is a small but significant anatomical space located near the porta hepatis of the liver. This triangle is of great clinical importance, particularly in laparoscopic cholecystectomy (gallbladder removal surgery). Understanding its borders, contents, and variations is crucial for surgeons to avoid complications.

Anatomical Borders

Calot’s triangle is oriented with its apex directed toward the liver. It has three key borders:

Historical Note: In the original 1891 description by Jean-François Calot, the superior border was defined as the cystic artery. However, modern anatomical definitions use the inferior surface of the liver, as the cystic artery shows significant variation in its course.

Diagram: Calot’s Triangle and Its Borders

Contents of Calot’s Triangle

Calot’s triangle contains several vital structures:

Clinical Relevance: Calot’s Triangle in Laparoscopic Cholecystectomy

Calot’s triangle is of paramount importance in laparoscopic cholecystectomy, the most common surgical procedure for gallbladder removal.

Surgical Importance

• The triangle is carefully dissected to identify anatomical variations and avoid complications.
• The right hepatic artery must be properly visualized before ligating the cystic artery.
• If the triangle is severely inflamed or obscured, a surgeon may:
  • Perform a subtotal cholecystectomy (partial removal of the gallbladder).
  • Convert to open surgery for better visualization.

Complications if Misidentified

Failure to correctly identify structures in Calot’s triangle can lead to:

• Bile duct injury – accidental cutting of the common hepatic or bile duct.
• Hemorrhage – injury to the hepatic artery or cystic artery.
• Biliary leakage – improper ligation of the cystic duct.

Points to Remember

Borders: Common hepatic duct (medial), cystic duct (inferior), and inferior surface of the liver (superior).
Contents: Right hepatic artery, cystic artery, lymph node of Lund, and lymphatic vessels.
Clinical Significance: Important for laparoscopic cholecystectomy, as proper identification of its contents prevents surgical complications.
Variation: The cystic artery has an unpredictable course, making careful dissection critical.

Bibliography & Further Reading

1. Calot J-F. Sur la cholécystectomie et sur la voie biliaire principale. 1891.
2. Strasberg SM, et al. “Anatomic Misunderstandings and Surgical Complications in Laparoscopic Cholecystectomy.” Annals of Surgery, 1995.
3. TeachMeAnatomy. Calot’s Triangle & Hepatobiliary Anatomy.