CHINA -- Doctors in China have solved a mystery that had been plaguing a man for years, They discovered a 4 inch dagger in the man's head that had been lodged there for four years.

Mr. Ni told doctors that he had been suffering from a severe headache but was unable to figure out why.

After a careful examination, doctors discovered a metal substance in his head that turned out to be a knife.

"We checked his mouth, but no wound or scar has been found. It is very strange as to how the blade got into his head," said Xu Wen, deputy director of the stomatology department of the People's Hospital in Yuxi city.

Mr. Ni was stabbed in the lower right jaw when fighting with a robber four years ago, according to officials. After the attack, he began to suffer from frequent headaches, bleeding in his mouth and had difficulty swallowing food. His voice also became hoarse and spoke gibberish. He had been to the hospital several times but no one could find out what was causing the symptoms.

"As time goes on, I used injections to kill pains in head and ears. It is now already four years," Mr. Ni told doctors.

The rusty blade did not touch the brain artery nor did it affect important facial nerves, doctors said. That's what kept him alive.

He is now recuperating at the hospital and is expected to survive