Massa's crash explained (UK users only)
By Andrew Benson
BBC Sport at the Hungaroring
Formula 1 is to conduct an investigation into the accident in which Ferrari driver Felipe Massa suffered a fractured skull.
The probe will attempt to discover the causes of the incident and whether any changes are required to improve safety.
Brazilian Massa was hit on the helmet by a spring that had fallen off Rubens Barrichello's Brawn GP car during Hungarian Grand Prix qualifying.
Massa underwent surgery and is under sedation following a scan on Sunday.
His accident came six days after 18-year-old Henry Surtees was killed after being hit on the head by a wheel from a crashed car in a Formula Two race in England.
The investigation into Massa's incident will be conducted by F1's governing body the FIA and the Brawn team. Barrichello's car suffered a failure in its rear suspension as the Brazilian, one of Massa's closest friends, went through Turn Three of the Hungaroring during final qualifying.
The spring came off the car and bounced along the track until Massa's Ferrari came on to the scene four seconds later.
The spring hit the front left-hand side of Massa's helmet when he was travelling at 162mph. His feet were on both the accelerator and the brake before he hit the barrier at Turn Four, at which point he had slowed to 62mph.
Insiders believe Massa's life may have been saved by the latest generation of carbon-fibre helmets, which were introduced four years ago and are approximately twice as strong as their predecessors.
Something broke on my car - Barrichello
The stronger helmets are one of a number of improvements that have been made in recent years to protect drivers' heads. Cockpit sides have been raised and the drivers wear a head and neck restraint device to protect them from the high G-forces involved in accidents.
Brawn team boss Ross Brawn described the incident as "a freak accident" and said F1 needed to fully investigate what had happened before deciding whether changes needed to be made.
"We need to keep a perspective on it - from what's been seen last weekend and this, we need to have a proper study to see if we need to do anything," he said.
"We need to digest what's happened and understand it properly.
"It is time to look at the whole thing and take a balanced approach. You can have covers or canopies but you have to be able to get at the driver and extract him if there is an accident.
"And you don't want anything that collapses down on a driver.
"It is something we will look at. In the history of F1 it is a fairly rare occurrence, but we must take it seriously and see what we can do.
"If there's a need to react, I'm sure F1 will promptly. But we must make sure we don't do something that makes the situation worse."
Additional reporting by Sarah Holt