A couple was reportedly arguing and pulled over on the side of the road at that location. A witness saw them acting strangely and called 9-1-1, officials said.
The deputy arrived and was speaking to the witness about the situation.
The witness went to leave in a vehicle that was hauling a trailer. The trailer hit the deputy as the witness drove away, knocking her down.
The deputy's ankle was broken in two places. She was taken by ambulance to North Cypress Medical Center.
According to officials, the man and woman who prompted the original call were each charged -- one with public intoxication and the other with interfering with the duties of a public servant.