What structures are involved in a left hemicolectomy?

In a left hemicolectomy, the surgical procedure involves removing a portion of the colon that is located on the left side of the abdomen. Specifically, this procedure typically includes the resection of the descending colon and the sigmoid colon. The sigmoid colon is the terminal section of the large intestine that connects to the rectum, while the descending colon runs along the left side of the abdomen. The purpose of a left hemicolectomy is often to treat conditions such as colorectal cancer, diverticulitis, or other diseases affecting this part of the colon.

The other structures mentioned in the incorrect options are not involved in a left hemicolectomy. The appendix and cecum are associated with the right side of the colon, while the terminal ileum and ileocecal valve also pertain to the right side of the gastrointestinal tract. The gallbladder and pancreas are entirely unrelated to colonic surgery as they pertain to the biliary and digestive systems in different contexts. Thus, understanding the anatomical focus of a left hemicolectomy clarifies why the descending and sigmoid colons are the correct structures involved in this surgical procedure.