On July 22, 2019, about 0317 eastern daylight time, United Airlines flight 860, a Boeing B767-322, N663UA, encountered turbulence during cruise flight about 200 nm north of San Juan, Puerto Rico. Of the 218 passengers and crew onboard, one flight attendant was seriously injured, and one flight attendant sustained minor injuries. The airplane was not damaged. The regularly scheduled international passenger flight was operating under 14 Code of Federal Regulations Part 121 from São Paulo/Guarulhos International Airport (SBGR), Sao Paulo, Brazil, to Washington Dulles International Airport (KIAD), Dulles, Virginia. According to the flight crew, they were in level cruise flight at flight level 360 when they started experiencing some chop. The captain turned on the seatbelt sign and instructed passengers to be seated over the public address system. Shortly after, the airplane experienced 3-5 seconds of moderate turbulence as they penetrated a cloud. The crew reported that the weather radar was operational and not showing any indications of precipitation along the route of flight. When the turbulence occurred, a flight attendant (FA) in the aft galley was reaching for the handset to repeat the seatbelt instructions in Portuguese when she was thrown sideways, then to the ceiling, and then back to the floor. The injured FA was helped to a jumpseat and attended to by a passenger physician for the remainder of the flight. Paramedics met the airplane at the gate in KIAD and the injured FA was transported to the hospital where she was diagnosed with multiple contusions and a fractured vertebra.