Category/ Stage 4 Subcutaneous tissue loss.

Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present on some parts of the wound bed. Often include undermining and tunneling. Be aware that the depth here varies by location for example on an ear where subcutaneous tissue is not present; stage IV wounds can extend into muscle and supporting structures.


In the USA NPUAP have added two further categories which may be referred to as stage 4
in other classification systems such as the one issued by EPUAP.