This woman was a pedestrian who was run over by a large, heavy truck. Note the severe amount of tissue disruption of her back, buttock, and leg. The wheel of the truck tore a large area of tissue off of her leg and avulsed most of the tissue of her buttock. Note the large amount of avulsed tissue that can be reflected. The term avulsion refers to the tearing away of tissues from their attachments. Avulsion may be a minor, local injury, or it may be severe and involve large areas of the body.