A 17-year-old pupil threw his teacher head-first onto a concrete floor like a "rag doll" before putting his feet on her desk, saying the "stupid cow deserved it." Kieran Matthew has been handed a community sentence after he left the woman unconscious in a pool of blood at St Paul's Academy in Dundee in March last year. Dundee Sheriff Court heard how the teacher had been left with an "extensive, significant scar" on her head following the horrific attack. The now 18-year-old had refused to get changed separately from other pupils before a PE class when he came "agitated and heightened." The measure had been in place for Matthew following previous aggression towards other pupils. He was accompanied by the teacher, who was deemed a "safe" person for him after previous de-escalating incidents before. However, when she tried to leave the room, Matthews pounced on her. Fiscal depute Laura Bruce said: "She recalls him gripping her in a rugby-style grip with her arms pinned to her sides and the next thing she felt was the horrific impact of her head striking the floor." The teacher was left briefly unconscious before she made a bloody handprint on the wall as she attempted to stand. Staff quickly rushed over to her after she screamed, with blood running down her head. Mrs Bruce added: "Another teacher had witnessed the accused lift her completely off her feet, throwing her to the floor deliberately and landing headfirst. Another said she appeared to be like a ragdoll flying through the air." Matthew then sat at the teacher's desk and repeatedly claimed "the stupid cow deserved it." The teen, who has ADHD, pleaded guilty to seizing the teacher's neck and body, throwing her to the floor, causing her to strike her head, and rendering her unconscious. Matthew admitted the assault was to her severe injury, permanent disfigurement, and the danger to her life. Sheriff Tim Niven-Smith said: "She has dedicated her life to vulnerable school children such as you. "You have robbed her of her career as she has been unable to go back to school due to panic attacks, nightmares and night terrors as a result of this assault." The offence merited 18 months in custody, according to the Sheriff. However, he said it would be reduced following an early guilty plea. Solicitor Theo Finlay, defending, said: "He has had longstanding issues managing his emotions. "It is likely he was already in a heightened condition. He experiences nightmares and requires to be medicated. He described becoming agitated. "The teacher moved others away, which made him feel more agitated and singled out. At school he felt intensely disliked and frequently provoked by his peers." Matthew was ordered to be under social work supervision for three years, must attend a mentoring course including anger management, and be placed on a one-year curfew.