On September 6, 2011, at about 1209 EDT, Southwest Airlines flight 983, a B737-700, N936WN, encountered turbulence enroute from Chicago Midway International Airport (MDW), Chicago, Illinois, to Fort Lauderdale-Hollywood International Airport (FLL), Fort Lauderdale, Florida. Of the five crew members and 137 passengers on board, one flight attendant received seriously injuries. The airplane was not damaged. According to flight crew statements, air traffic control informed them to expect turbulence from thunderstorms in mid to south Florida. In preparation for the possibility of turbulence, the captain called the flight attendants (FA) and advised them to close the galleys and to be seated and that they would likely be able to complete the cabin cleanup after clearing the weather at 10,000 feet. The flight deviated west of the weather and mostly smooth conditions were experienced for about 20 minutes during the descent. As the flight descended below about 14,000 feet, the flight momentarily encountered "large bumps" and two FAs were thrown to the floor after having just gotten out of their jump seats to finish cleaning up the aft galley. As a result, one FA experienced severe pain in her leg and was unable to complete her duties for the remainder of the flight. The captain was immediately informed of the injured FAs condition and medical assistance was requested to meet the airplane at the gate. After an uneventful landing, the FA was transported to the hospital and diagnosed with a broken leg.