A jury heard this week that a man growled like a dog as he sank his teeth into his girlfriend's finger during an argument.
Moments earlier, the court heard the man had yanked the steering wheel from her hands a she drove along the M1, causing the car to skid onto the hard shoulder and burst a tyre.
Zoe Page was giving evidence at St Albans crown court where her ex, 33 year-old Alvin Worrell of Bushey Grove Road, Bushey, is on trial.
He pleads not guilty to assault by beating on November 2 last year and causing grievous bodily harm with intent a week later.
The court heard the pair had been in a relationship that at first was happy but, by November of last year, she wanted to end it as it began to deteriorate because of his controlling and possessive ways.
Miss Page told the court that in April last year the defendant bought her a car for her 21st birthday, but by the summer of that year things between them began to go down hill.
She said on November 2 during an argument outside a shop in Vicarage Road at around nine o'clock in the morning, the defendant spat in her face.
Simon Wiltshire for the prosecution told the jury that act amounted to assault by beating.
The woman then told the court that a week later she and Mr Worrell had been driving back to Watford from a shopping trip to St Albans when they began arguing just after she had got on the M1 at junction 6.
During the exchange of words she told him: "I don't want to be with you anymore."
Miss Page said with that, the defendant told her: "If I can't be with you no one else can" and, without warning, he "yanked" down on the steering wheel as she drove causing her car to go onto the hard shoulder and strike the kerb, puncturing the tyre.
She said he then grabbed her right hand and bit her hard on the middle finger on her right hand.
"He was growling like a dog as he did it," she told the jury.
Miss Page told the court she managed to get out of the car and was thinking about changing the wheel when the defendant got out from the passenger side and pushed her to the ground.
She said he then bit her on the ring finger of her right hand.
The jury heard how she then fled the scene running along the motorway until she found herself by a school in Mount Pleasant Lane where a young woman walking her dog came to her aid and took her into her home.
The jury were told Miss Page suffered damage to the tendons of her fingers caused by the defendant's biting.
In addition, she suffered an infection that spread up the hand to her elbow and had to undergo two lots of surgery at The Royal Free Hospital in Hampstead where she remained for two days.