Jeronimo Uribe tells The Associated Press via text message Friday that his father lurched forward and hit his chest in Wednesday's fall but was not hospitalized.
He says his 59-year-old father fell while riding in Monteria, the capital of the province where the former president has a ranch.
Alvaro Uribe was president from 2002 to 2010. He is a practiced equestrian and as president often rode for visiting dignitaries.
Colombians were first alerted to the injury in a tweet by current President Juan Manuel Santos, who wished his predecessor a quick recovery.