On April 15, 2002, at 1055 Pacific daylight time, a Northwest Airlines Airbus Industrie A319-114, N325NB, encountered moderate turbulence while descending for the approach to the Reno, Nevada, airport, and one flight attendant sustained serious injuries. The aircraft was operated under the provisions of 14 CFR Part 121by Northwest Airlines, Inc., as flight 1515, a regularly scheduled domestic passenger flight from Minneapolis, Minnesota, to Reno. The airplane was not damaged. There were no other injuries to the 2 airline transport pilot licensed pilots, 4 remaining flight attendants, or 61 passengers. Visual meteorological conditions prevailed. An instrument flight rules flight plan had been filed for the flight, which departed from Minneapolis at 0930 central daylight time as a nonstop flight to Reno. According to the captain's written statement, when the flight was initially cleared to descend from FL390 to 15,000 feet by Oakland Air Route Traffic Control Center, they were advised to expect moderate turbulence while descending into the Reno airport area. He then briefed the lead flight attendant on the expected turbulence encounter and asked that the cabin be secured early, with everyone including the flight attendants in their seats with seat belts secured. The captain then prearranged a chime signal with the lead flight attendant that would mean everyone should be in their seats. Prior to reaching 15,000 feet, the flight was handed off to Reno TRACON and the controller cleared the flight to 11,000 feet and advised of preceding pilot reports of moderate turbulence from 15,000 to 11,000 feet on the approach to the airport. The flight crew then gave the prearranged chime signal. A short time later, as the flight was nearing 11,000 feet and was encountering the turbulence, the first officer called the lead flight attendant on the interphone and asked if the cabin was secure and he received an affirmative response. Just after that conversation, the airplane experienced what the crew described as a "severe jolt." The flight attendant then called to advise them of the injury and a medical emergency was declared. The injured flight attendant was interviewed by a Federal Aviation Administration inspector from the Reno Flight Standards District Office on April 17, 2002. Her statement was consistent with the written statements provided by the other cabin crewmembers. She reported that they were briefed by the lead flight attendant on the expected turbulence encounter and the cabin crew secured the cabin early. When the chime signal was heard, she and the other attendants took their jump seats and fastened their restraint systems. Her seat was in the rear near the aft galley facing aft. The other attendant assigned to the rear galley was in a jump seat facing forward. As the flight was encountering the moderate turbulence, she noticed that one of the aft galley upper compartment doors had come open. This compartment was in line with both her head and the other attendants head, and she was concerned about objects coming out of the compartment on landing and injuring either one of them. She unfastened her restraints, got up and secured the door. As she was returning to her seat, the airplane encountered a severe jolt, which violently slammed her into the ceiling, then the floor.