What is another term for a hairline fracture?

A hairline fracture is commonly referred to as a stress fracture. This type of fracture occurs due to repetitive stress or overuse, leading to tiny cracks in the bone without a distinct separation of the bone fragments. Stress fractures often develop gradually over time, particularly in athletes or individuals participating in activities that exert repetitive pressure on certain bones.

In contrast to the other types of fractures listed: a complete fracture involves a break that separates the bone into two or more pieces; a greenstick fracture is an incomplete fracture typical in children, where the bone bends but does not break entirely; and a pathological fracture occurs due to an underlying condition that weakens the bone, such as osteoporosis or a tumor. These distinctions clarify why "stress fracture" is the appropriate synonym for hairline fracture.