One appliance and crew from Gerrards Cross, one from Hertfordshire and one from Amersham attended, along with an officer.
A lorry had been involved in a collision with a concrete barrier underneath a bridge. The motorway was closed by national Highways.
The firefighters provided immediate emergency care to one man, who was out of the lorry when they arrived. He was passed into the care of South Central Ambulance Service.
The incident was left in the hands of Thames Valley Police and National Highways.