Which type of ostomy affects the lower colon?

The presence of a colostomy indicates that the ostomy is specifically created from the colon, which is part of the lower gastrointestinal tract. A colostomy involves diverting the colon to an external stoma, allowing for the passage of stool to be collected in a bag outside the body. This procedure is typically done in cases where a portion of the lower colon is diseased or needs to be bypassed due to conditions such as cancer, inflammatory bowel disease, or severe trauma.

In contrast, an ileostomy involves the diversion of the ileum, which is the last part of the small intestine, while a urostomy relates to diverting urine from the urinary system. A duodenostomy, although less common, involves the duodenum, which is the first section of the small intestine. Therefore, a colostomy is the only option outlined that directly pertains to the lower colon, confirming it as the correct answer.