Which artery is most at risk of injury during dissection of Calot's triangle during open cholecystectomy?

Explanation

## Vascular Anatomy of Calot's Triangle **Key Point:** The right hepatic artery is the critical vascular structure within Calot's triangle and is at highest risk of iatrogenic injury during cholecystectomy. ### Arterial Boundaries of Calot's Triangle | Structure | Location | Risk Level | | --- | --- | --- | | **Right hepatic artery** | Superior boundary of triangle | **HIGH** — within triangle | | Cystic artery | Branch of right hepatic artery | Moderate — must be identified and ligated | | Left hepatic artery | Lies in left part of hepatoduodenal ligament | Low — outside triangle | | Gastroduodenal artery | In hepatoduodenal ligament, inferior to triangle | Low — outside triangle | **High-Yield:** The right hepatic artery forms the superior boundary of Calot's triangle and is the most commonly injured vessel during cholecystectomy if dissection is not meticulous. ### Anatomical Variants **Warning:** Anatomical variations of the right hepatic artery occur in 25–40% of the population: - Anomalous origin from superior mesenteric artery - Anomalous origin from gastroduodenal artery - Crossing anterior to the common hepatic duct These variants increase the risk of injury if not recognized preoperatively. ### Clinical Significance **Clinical Pearl:** Proper identification of Calot's triangle boundaries (especially the right hepatic artery) is essential before ligating the cystic artery. The cystic artery is a branch of the right hepatic artery and must be individually identified and divided. **Mnemonic:** **RAC** = **R**ight hepatic artery (at risk), **A**rtery (cystic), **C**ystic duct (safe to divide once artery is secured) [cite:Standring Anatomy 42e Ch 63]