What patient position is used for a flex sigmoidoscopy?

• A. Supine
• B. Sims or Knee-Chest
• C. Prone
• D. Fowler's position

Answer: (B)

Positioning for a flex sigmoidoscopy aims to align the rectum and sigmoid colon so the scope can be inserted smoothly and visualize the area clearly. The Sims (left lateral) or knee-chest position accomplish this by straightening the lower colon and reducing looping, which makes advancing the scope easier and improves exposure to the rectosigmoid region. In the Sims setup, the patient lies on the left side with the upper knee flexed toward the chest; gravity helps open the sigmoid and gives better access to the anal canal. In the knee-chest position, the patient is on hands and knees with hips elevated, which similarly straightens the colon and aids scope advancement. By contrast, supine (on the back), prone (on the stomach), or Fowler’s (upright) positions don’t provide the same favorable angle or exposure for reaching the sigmoid area during this procedure.