Which of the following is a type of convexity?

• A. Rigid
• B. Elastic
• C. Shallow
• D. Flat

Answer: (C)

Convexity refers to the curve of the baseplate and how it presses against the skin to help form a seal around the stoma. A shallow convexity is a mild curved profile used when the stoma sits flat or is slightly recessed; the gentle outward pressure helps push peristomal skin away from the opening and creates a better seal without applying excessive force that could irritate the skin. The other terms describe material or surface characteristics rather than the shape of the barrier: rigid indicates stiffness, elastic refers to stretchiness, and flat means no convex curve at all. So the type of convexity here is shallow, since it denotes a mild convex curve used to improve sealing for less-protruding stomas.