How are round stomas measured?

• A. Circumference of stoma
• B. Length of stoma
• C. Diameter of stoma
• D. Volume of stoma

Answer: (C)

For a round stoma, the most important measurement is the diameter. The appliance opening must match the stoma’s circular opening, so you measure straight across the widest part to determine its diameter. The opening is usually chosen to be slightly larger than the measured diameter to allow for swelling and to prevent constriction, which helps prevent skin irritation and leakage.

Circumference isn’t used as the primary sizing metric because it requires conversion to diameter and adds unnecessary steps. The length refers to how far the stoma protrudes above or sits below the skin, which affects fit with convexity but not the size of the opening. Volume isn’t a factor in sizing the stoma opening.

So, the diameter is the best measure to guide the correct appliance size for a round stoma.