How can ribs commonly fracture?

Ribs commonly fracture primarily through crushing injuries and direct blows to the thoracic cage. This is due to the structure of the ribcage, which is designed to protect vital organs such as the heart and lungs but can become vulnerable under significant external force. When subjected to trauma—such as in sports, falls, or accidents—the ribs can crack or break as the pressure exceeds the bone's inherent strength.

In contrast, excessive stretching is less likely to cause rib fractures, as ribs are more susceptible to direct impact rather than tensile forces. Bending forward typically does not exert the kind of force on the ribs that would lead to fractures. Lastly, cold temperatures may impact muscle function and joint mobility but do not directly cause bones such as ribs to fracture. Thus, the mechanics of rib injury strongly support the notion that direct trauma to the thoracic cage is the most common cause of rib fractures.