A back support apparatus intended for use during emergency transport of a patient suffering an actual or suspected spine injury is disclosed. The device provides a solid support for the arched portion of the spine that molds to the shape of the individual patient's back. The device comprises a bag or other container into which a solid curable material and a liquid activator are introduced; which is then placed beneath the patient's spine on a back board or like support. The device may be deployed quickly without the need for additional straps, belts, or the like, and may be treated as disposable due to its low cost.