Which type of fracture does not involve a break in the skin?

A closed fracture is characterized by the fact that the skin over the fracture site remains intact, meaning there is no external wound caused by the broken bone. This type of fracture generally allows for a lower risk of infection since the skin barrier is not breached, unlike an open fracture where the bone is exposed to the external environment. In closed fractures, the break can still be significant and may involve various fracture patterns, but the key distinguishing feature is the absence of an associated skin break.

The other types of fractures listed have different characteristics; an open fracture, for example, involves a break in the skin and exposes the bone, leading to higher infection risks. Comminuted fractures consist of multiple bone fragments, which can either be open or closed, while spiral fractures occur when a twisting force is applied and can also be classified as either open or closed depending on the preservation of the skin. Understanding these distinctions helps in assessing fracture types in a clinical context.