In wound assessment, which statement about tunneling and undermining is correct, and how is their depth documented?

• A. Tunneling is a radiographic term used to describe bone involvement.
• B. Tunneling is a narrow channel extending from the wound bed; undermining is tissue destruction under wound edges causing a hollow; depth is recorded relative to the wound margins using a clock reference and measured with a sterile probe.
• C. Tunneling is a superficial channel on the skin surface; undermining is infection around the wound; depth is never measured.
• D. Tunneling refers to depth measurement measured with a ruler.

Answer: (B)

Understanding wound assessment hinges on how tunneling and undermining are defined and documented. Tunneling is a narrow channel that extends from the wound bed into surrounding tissue. Undermining is tissue destruction under the wound edges that creates a hollow beneath intact skin. For depth, providers document relative to the wound margins using a clock-face reference (for example, describing how deep at 6 o’clock or along 3 o’clock) and measure with a sterile probe to determine how far the tunnel or undermining extends. This clock-based approach with a sterile probe gives a standardized, reproducible way to describe wound architecture and track healing over time.

This isn’t a radiographic term about bone involvement, and undermining isn’t defined by infection. Depth is not measured with a ruler; the clock reference and sterile probing method are the standard.