**Question:** Left trisegmentectomy involves removal of

A. S6, S7, and S8 segments
B. S4, S5, and S6 segments
C. S3, S4, S5, and S6 segments
D. S2 and S3 segments

**Core Concept:** Trisegmentectomy is a surgical procedure that involves the complete removal of three liver segments based on Couinaud's segmentation system. In this system, the liver is divided into eight segments, each named for the vessels that supply it (Vena Cava and Portal Vein).

**Why the Correct Answer is Right:** Left trisegmentectomy removes S6, S7, and S8 segments. These segments are removed because they are supplied by the left portal branch of the portal vein, which is responsible for the blood supply to the left lateral section of the liver.

**Why Each Wrong Option is Incorrect:**

A. S6, S7, and S8 segments are the correct answer, not S6, S7, and S8 plus S10 (option A).
B. S4, S5, and S6 segments are incorrect because they are supplied by the right portal branch, not the left portal branch, which is responsible for the blood supply to the left lateral section.
C. S3, S4, S5, and S6 segments are incorrect because they are supplied by the right portal branch and not the left portal branch, which supplies S6, S7, and S8 segments.
D. S2 and S3 segments are incorrect because they are supplied by the right portal branch, not the left portal branch, which supplies S6, S7, and S8 segments.

**Clinical Pearl:** Understanding liver segment anatomy is crucial for surgeons performing liver resections, as the choice of segments to remove depends on the blood supply and the location of the tumor or abnormality being resected.

**Correct Answer:** S6, S7, and S8 segments

**Explanation:** Left trisegmentectomy involves the removal of three segments: S6, S7, and S8. These segments are chosen based on their blood supply from the left portal branch, which arises from the left lateral branch of the portal vein. When performing left trisegmentectomy, surgeons aim to remove the tumor or abnormal tissue while preserving as much normal liver tissue as possible, ensuring proper liver function and reducing the risk of complications post-surgery.