Kangana is essaying the iconic role of Rani Laxmibai of Jhansi in the movie, which is helmed by Krish.
According to sources close to Kangana, the accident took place last night when she was performing a scene at Jodhpur's Mehrangarh fort, where she had to jump off from a 40-feet-high wall with her adopted child in the film, who is tied to her back on a horse.
"She was taken to a hospital immediately and it has been discovered that it is a ligament tear. She has been advised rest for one week," sources added.
The "Queen" actor already finished shooting for major action sequences last month and this was the final dangerous stunt left.
Earlier in July, Kangana got severely injured during a sword-fighting sequence with co-star Nihar Pandya, when the latter's sword accidentally hit her forehead, causing a deep cut.
"Manikarnika..." is scheduled to be released in April.