Can a collapse lung occur in a collision if wearing your seatbelt under your arm?

Yes, wearing a seatbelt under your arm can increase the risk of a collapsed lung (pneumothorax) during a collision. This improper positioning can lead to excessive force on the chest and ribcage, potentially causing rib fractures or direct trauma to the lungs. In a crash, the seatbelt's restraint may not distribute force evenly, exacerbating the risk of injury. Always wear seatbelts properly across the lap and over the shoulder to minimize such risks.