Ex-MLA Kanwar Lal Meena, jailed for a 2004 incident involving a pistol threat to an officer, was injured after a bathroom fall on Wednesday.
Doctors at Jhalawar Medical College confirmed he sustained a spinal fracture and remains under treatment.
The injury comes as Anta assembly seat heads for a November 11 bypoll, with BJP, Congress, and an Independent in the fray.
Former BJP MLA from Anta seat in Baran district, Kanwar Lal Meena, who is undergoing a three-year incarceration in Jhalawar jail for pointing a pistol at a civil servant 20 years ago, has sustained a spinal fracture after he slipped in the prison bathroom, an official said.
The prison's jailor, Nandram, said the incident occurred on Wednesday evening, and the inmate was rushed to the government medical college and hospital in Jhalawar.
Its dean, Dr Sanjay Porwal, said Meena was admitted to the hospital on Wednesday night and he has sustained a spinal fracture.
When contacted, Jhalawar jail's deputy superintendent Niranjan Sharma avoided speaking on the matter, saying he was busy.
Anta assembly seat is set for bypoll on November 11, with Congress fielding Pramod Jain Bhaya and BJP naming Morpal Suman as its candidate. Naresh Meena is an Independent candidate in the bypoll.
