An elderly female driver suffered a broken hip, broken ribs and a punctured lung in a head-on collision with a tractor at Syderstone, near Fakenham.
Police said the woman is from the local area.
Officers from Acle Road Policing and are appealing for witnesses to provide information.
The collision which took place yesterday afternoon.
At approximately 5.15pm, the woman was driving a green Perodua Myvi, travelling along Tattersett Road towards South Creake when she was in a collision with a green John Deere tractor heading in the opposite direction.
PC Andrew Poole, from Acle Road Policing, would like to hear from anyone who witnessed the incident or the manner of driving of either vehicle prior to the collision.
PC Poole can be contacted on 101.
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