This harrowing picture shows an X-ray of a 15-year-old boy's skull after a five inch knife was plunged into his head.
Amazingly the teenager survived the stabbing and ten months on from the attack has enrolled in college.
The boy and two other youngsters were attacked when they tried to stop a friend being robbed at a bus stop in Walworth, south London.
The muggers responded by using a kitchen knife to stab one of the boys in the forehead, another twice in the back and a third in the shoulder.
He survived because he was rushed to hospital with the knife still sticking out of his head and doctors managed to operate in time.
X-rays released by police show how deep the knife penetrated, while still missing the boy's brain. Surgeons said if anyone had tried to take it out he would have died.
The boy's two friends also recovered after the attack outside Tesco in the Old Kent Road on 28 November.
One of the muggers dropped a hat and his mobile at the scene and was arrested later at his home.
The boy, 17, was found guilty at Inner London Crown Court last week of attempted murder and two counts of GBH with intent.
He will be sentenced next month. Officers are still hunting the other two attackers.
Meanwhile, a 27-year-old man is in a serious condition after being stabbed repeatedly in Dudden Hill Lane in Willesden early today.