Colonoscopy Position: Left Lateral Decubitus with Flexed Knees

The standard starting position for colonoscopy is left lateral decubitus (left side lying) with hips and knees flexed toward the chest.

Why This Position

• Opens the angle at the sigmoid-descending colon junction.
• Allows gravity to pool luminal fluid away from the scope tip.
• Facilitates scope advancement through the sigmoid colon (often the most technically challenging segment).

Position Changes During Procedure

• Supine: For transverse colon, hepatic flexure.
• Right lateral: For cecal intubation, terminal ileum.
• Prone / prone with hip extension: Occasionally for difficult cecal access or polyp resection.
• Abdominal pressure (by assistant) often used to straighten loops.

Patient Comfort

• Conscious sedation (midazolam + fentanyl) or monitored anesthesia care (propofol).
• CO₂ insufflation (less pain vs. air).
• Water immersion/exchange techniques reduce distension.

Position changes are routine and guided by endoscopist to optimize visualization and safety.