Final answer:
The wound with broken skin and black eschar covering the base on the coccyx is staged as unstageable, as the depth cannot be determined until eschar is removed.
Step-by-step explanation:
A patient with a broken skin on his coccyx that has black eschar covering the base of the wound would have the wound staged as unstageable. According to the National Pressure Ulcer Advisory Panel (NPUAP), a wound is considered unstageable when the base of the ulcer is covered by slough (yellow, tan, gray, green, or brown) and/or eschar (tan, brown or black) in the wound bed. The presence of eschar, a black necrotic tissue, indicates that full thickness tissue loss has occurred, but the actual depth of the wound and the involvement of underlying tissues cannot be determined until the eschar is removed.