Mechanisms of Fractures

Bones can fracture by a number of different mechanisms:

Direct violence

• Direct blow to the bone e.g. road traffic accident.

Figure 1 - Example of how direct violence may occur

Indirect violence

• No actual violence or contact is applied to the site of the fracture
• Such a fracture most commonly occurs as a result of a twisting injury.

Pathological fractures

• Factures occur in bone which have been weakened already due to a pathological process.

Figure 1 - Pathological fracture (Metastatic lesion proximal femur)

Fatigue (stress fracture)

• Occur as a result of repetitive stress.

Figure 2 - Stress fracture third metarsal in a runner

Describing a Fracture