On November 6, 2002, at 0945 eastern standard time, a McDonnell Douglas MD-82, N479AA, registered to and operated by American Airlines, Inc. as flight 1258, encountered turbulence during descent into Orlando International Airport, Orlando, Florida. The scheduled air carrier flight was operated under the provisions of Title 14 CFR Part 121, and instrument flight rules (IFR). Visual meteorological conditions prevailed and an IFR flight plan was filed. The airline transport-rated Captain, the airline transport-rated first officer, two flight attendants, and 71 passengers were not injured, and one flight attendant received a serious injury. The airplane was not damaged. The flight departed Dallas-Fort Worth International Airport, Dallas, Texas, at 0637 central standard time. According to the Captain, while on initial approach into Orlando International Airport, descending out of 11,000 feet at 250 knots, the airplane encountered a moderate bump of turbulence, about one second in duration. The captain stated that the airplane was skimming a broken layer of clouds with about 2,000 feet of vertical buildup. He stated that the preparation for landing public address was given about six minutes before the airplane encountered the turbulence. According to the Captain, there was nothing on the radar or visual observation of the sky condition to suggest any more than light turbulence. The number one flight attendant stated that the Captain told the flight attendants that there might be turbulence ahead and for them to clean up and sit down. She stated that they were in the process of cleaning up "when it got really bad," and she had to hold onto the seatback. She stated that she saw the number two flight attendant's legs extending into the aisle. The number one flight attendant stated that the number two flight attendant had fallen onto her ankle and she helped her into her seat. The number one flight attendant stated that the ankle swelled up "huge." She stated that she notified the Captain and got an ice pack for her. Upon arriving at the passenger terminal gate, emergency medical personnel put a splint on the injured flight attendant's ankle and transported her to the hospital, where it was later discovered that her ankle was broken.