On November 23, 2010, about 1340 central standard time, a passenger received serious injuries while deplaning from an Embraer EMB-145LR, N678AE, registered to and operated by American Eagle Airlines under the provisions of 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight on an instrument flight rules flight plan. The airplane was piloted by an airline transport pilot. Except for the one passenger injury, there were no injuries to the other passengers or crewmembers. The flight originated from the Dallas/Fort Worth International Airport (DFW), Dallas-Fort Worth, Texas, at 1140, and had arrived at the Dane County Regional Airport-Truax Field (MSN), Madison, Wisconsin. According to crew statements, the injured passenger was designated as a wheelchair passenger and had boarded the airplane wearing an ankle brace. The passenger was seated in seat 9A. According to the gate agent, the passenger had been instructed to remain seated and wait for assistance which would be provided after the other passengers had deplaned. The flight attendant reported seeing the passenger walking down the cabin aisle during passenger deplaning without her crutches. The crutches had been stowed in the crew closet of the airplane for the flight. The flight attendant reported that the passenger fell in the aisle of the airplane's cabin near the forward galley. After falling, the passenger complained of pain in her right foot. Paramedics were called and assisted the injured passenger off of the airplane using a wheelchair. It was later determined that the injured passenger had broken both of her ankles and required surgery.