Which of the following is NOT a type of closed fracture?

A closed fracture is defined as one where the bone is broken but there is no open wound in the skin. Among the options provided, a compound fracture is characterized by the bone breaking and protruding through the skin, which distinguishes it from closed fractures.

Simple fractures, greenstick fractures, and comminuted fractures all fall under the category of closed fractures because, despite their differences in structure and severity, they do not expose the bone to the external environment. In contrast, a compound fracture requires different medical management due to the increased risk of infection and complications.

By recognizing these characteristics, it becomes clear that compound fractures are not classified as closed fractures, making this the correct response to the question.