thumb|A Posey Straitjacket (small-size) manufactured by The Posey Company. A straitjacket is a garment shaped like a jacket with long sleeves that surpass the tips of the wearer's fingers. Its most typical use is restraining people who may cause harm to themselves or others. Once the wearer's arms are in the sleeves, the person restraining the wearer crosses the sleeves against the chest and ties the ends of the sleeves to the back of the jacket, ensuring the arms are close to the chest with as little movement as possible.