A doctor was injured when a prisoner tried to escape during a routine medical appointment at a hospital in North Lanarkshire.
The 31-year-old inmate from HMP Shotts was being escorted by G4S security staff when he tried to get away.
A doctor who tried to assist the security staff suffered minor injuries during the incident on Friday.
The Scottish Prison Service said an investigation had begun into what happened.
A spokesman said: "I can confirm there was an incident involving a prisoner from HMP Shotts at Wishaw General Hospital today.
"We will be working with Police Scotland in investigating the full circumstances of the incident."
A G4S spokesman said: "During a routine hospital appointment a prisoner attempted to evade custody but was immediately apprehended by G4S staff.
"The prompt actions of our officers averted a more serious incident and demonstrates the challenging situations our staff can face while carrying out their duties."