What is a body jacket?

An orthopedic cast. Is used to immobilize the trunk after spinal injuries or surgery.
Brace yourself... A body jacket is a rigid brace used to protect your spine by immoblizing it. It is custom fit for the individual; usually by an experienced orthopedist; and the user needs to be instructed in how to both put it on; and take it off. It can also be utulized to treat children with severe curvatures of the spine(or scoliosis).
"straight jacket" In the old days it used to be called a straight jacket, . This is a clothing that wraps around you to prevent arms from scratching or hurting self or others. It is used only when there is serious risk of danger.