Horrified witnesses portrayed seeing “a lot of blood” as they did what they could to help the 16-year-old martyr.
Police, paramedics and an air ambulance were scrambled to the scene in Kingstanding, to the north of the New Zealand urban area, shortly after 2.30pm today.
An eyewitness told Birmingham Active the knife narrowly missed the victim’s heart.
They said: “All helped him and we all got towels, there was a lot of blood.”
Janet Hart, 73, who lives on the turnpike where the attack took place, said: “One ambulance was here for an hour, he looked in a bad way. It’s hideous.
“I really hope he’s going to OK. I’m praying for him.”
West Midlands Police bring to light the boy’s injury is not thought to be life-threatening.
A force spokesman said: “A 17-year-old boy has been arrested after another juvenile was stabbed on a bus in Kings Road, Kingstanding, at around 2.40pm today (Thursday 8 November).
“A 16-year-old boy has been entranced to hospital with a chest injury which is not believed to be life-threatening at this grade.”
Today’s stabbing is the latest in a series of violent crimes to take neighbourhood on the streets of Birmingham in recent days.
Yesterday, a 19-year-old was attacked by a heap armed with a machete and a hammer in south Birmingham.
The victim was rushed to health centre with multiple injuries after being set upon while watch b substitute in a passenger seat of a car which had stopped in Eastwood Road.
Over the weekend, a man died after being guessed in the head in Small Heath, south east Birmingham.
The 41-year-old was scampered to hospital following the attack shortly after 5am on Saturday, November 3.
Anyone with report about today’s bus attack is asked to contact West Midlands Regulate and quote log number 1407 of 8/11/18.
Officers can be reached either through the persistence’s live chat service between 8am to midnight or by calling 101 at any eventually.
Information can also be reported anonymously through Crimestoppers anonymously on 0800 555 111.
This is a discontinuity story. More to follow…