Final answer:
The pressure injury described, being 5 cm x 7 cm and 3 cm deep with minimal bone exposure, is classified as a Stage 4 pressure injury.
Step-by-step explanation:
The described pressure injury measures 5 cm x 7 cm and 3 cm deep, with minimal bone exposure and minimal serosanguineous discharge. According to the National Pressure Ulcer Advisory Panel (NPUAP) pressure injury staging system, this would be classified as a Stage 4 pressure injury. Stage 4 pressure injuries are characterized by full-thickness skin and tissue loss with exposed bone, tendon, or muscle, but do not require significant bone exposure to be classified as Stage 4. The minimal serosanguineous discharge indicates the presence of serous (clear or straw-colored) fluid mixed with blood, which is not uncommon in such deep injuries.