A 52-year-old woman undergoes laparoscopic cholecystectomy for symptomatic cholelithiasis. During dissection of the Calot triangle, the surgeon identifies the most common anatomical variant of the cystic artery. Which of the following is the commonest origin of the cystic artery?

Explanation

## Anatomy of the Cystic Artery **Key Point:** The cystic artery is a branch of the hepatic arterial system that supplies the gallbladder and forms one boundary of the Calot triangle. ### Origin and Variants The cystic artery arises from the **right hepatic artery in approximately 80–90% of cases**, making it the most common origin. This occurs as the right hepatic artery passes through or near the Calot triangle before dividing into its segmental branches. | Origin | Frequency | Clinical Significance | | --- | --- | --- | | Right hepatic artery | 80–90% | Most common; standard anatomy | | Left hepatic artery | 5–10% | Rare; may cross anterior to common hepatic duct | | Gastroduodenal artery | 2–5% | Uncommon; increases risk of ischemia if ligated | | Celiac trunk / SMA | <1% | Extremely rare; anomalous origin | **High-Yield:** During cholecystectomy, the cystic artery must be identified and ligated before the cystic duct to prevent bleeding. Failure to recognize an anomalous origin can lead to inadequate hemostasis or injury to the parent vessel. ### Calot Triangle Boundaries The Calot triangle (also called the hepatocystic triangle) is bounded by: 1. **Medial:** Common hepatic duct 2. **Lateral:** Cystic artery 3. **Superior:** Right hepatic artery (or cystic artery origin) 4. **Floor:** Liver bed (segment IV–V junction) **Clinical Pearl:** Safe identification of the cystic artery within the Calot triangle is the cornerstone of safe laparoscopic cholecystectomy. The "critical view of safety" technique emphasizes clear visualization of two structures crossing the hepatocystic triangle (cystic artery and cystic duct) before division. **Mnemonic:** **CAD** — **C**ystic artery from **A**rtery (right hepatic), **D**uct (cystic) — the two structures to identify in the Calot triangle. [cite:Standring Anatomy 42e]