The victim has been flown off-island to receive treatment.
The incidnet happened between Gardeners Lane (Milntown) and Bircham Avenue this afternoon.
The Isle of Man Constabulary also said: ‘We will allow access to the schools if required but please avoid the area if possible.’
The Roads Policing Unit have appealed for witnesses around the area at the time to come forward.
You can contact them on 631212, quoting the reference number: P280922016