What two injuries must occur for a skull fracture to be classified as "open"?

For a skull fracture to be classified as "open," it is essential for there to be a rupture of the protective layers surrounding the brain, specifically the dura mater, as well as a disruption to the bone structure, typically referred to as a compound fracture. The torn dura indicates that there is a direct communication between the brain and the external environment, which significantly increases the risk of infection and other complications.

A compound fracture is characterized by the bone fragment breaking through the skin, which directly aligns with the definition of an open fracture. This combination of an injury to the dura and the presence of a compound fracture distinctly distinguishes it from other types of fractures or injuries that may not necessarily penetrate through to the brain or create an open pathway to the external environment. Therefore, both the torn dura and the compound fracture are critical components that define an "open" skull fracture, highlighting the severity and potential consequences of this type of injury.