A pathologic fracture occurs when:

A pathologic fracture occurs when normal forces are applied to abnormal bone structures. This type of fracture is not the result of high-impact trauma or excessive stress; instead, it occurs due to underlying conditions that weaken the bone, such as osteoporosis, tumors, or infections. In such cases, the bone's structural integrity is compromised, so routine activities or standard forces can lead to a fracture.

This concept differentiates a pathologic fracture from other types of fractures, where either abnormal forces are applied to normal bones or normal forces are experienced by normal bones, which would not typically result in a fracture. Understanding this distinction is essential for evaluating bone health and the risks associated with certain medical conditions.