What types of stomas is convexity used in?

• A. Flush or retracted stomas
• B. Protruding stomas
• C. Irregular stomas
• D. Stomas with high moisture skin

Answer: (A)

Convexity is used when the stoma sits flush with the skin or retracts below it. The convex baseplate has a curved, outward-dome shape that applies gentle pressure around the stoma, pressing the surrounding skin into the opening and creating a snug gasket-like seal. This helps prevent stool from leaking under the barrier and protects the peristomal skin. When a stoma protrudes above the skin, a flat barrier usually seals well, so convexity isn’t typically needed and can even cause discomfort by pressing on the protruding tissue. Irregular stomas or those with very moist skin require other adjustments for fit and adhesion, but the primary role of convexity is to manage flush or retracted stomas.