US Patent 7188382 Ankle bolster

This device is made to protect the bony surfaces of a foot from prolonged pressure and ultimate skin breakdown. It consists of a cylinder of dense foam that is fitted to encompass the lower leg of a user from the knee to the ankle. When in place on the leg a of a user lying in bed, it will support the lower leg such that the foot will not be in contact with the firm surface of the bed, thus providing total pressure relief to the foot. The user can also lie in any position, even prone, with out interference from this device.