The term boot refers to a family of instruments of torture and interrogation variously designed to cause crushing injuries to the foot and/or leg. The boot has taken many forms in various places and times. Common varieties include the Spanish boot (sometimes referred to as "scarpines") and the Malay boot. One type was made of four pieces of narrow wooden board nailed together. The boards were measured to fit the victim's leg. Once the leg was enclosed, wedges would be hammered between the boards, creating pressure. The pressure would be increased until the victim confessed or lost consciousness. Newer variants have included iron vises--sometimes armed with spikes--that squeezed feet and metal frames employed red-hot.
The Spanish boot was an iron casing for the leg and foot. Wood or iron wedges were hammered in between the casing and the victim's flesh. A similar device, commonly referred to as a shin crusher, squeezed the calf between two curved iron plates, studded with spikes, teeth, and knobs, to fracture the tibia and fibula.
Primitive forerunners of the archetype can be found dating back as far as a thousand years. The first Scottish effort also referred to as a buskin, made use of a vaguely boot-shaped rawhide garment that was soaked with water, drawn over the foot and lower leg, and bound in place with cords. The contraption was slowly heated over a gentle fire, drastically contracting the rawhide and squeezing the foot until the bones were dislocated, though there would not have been sufficient pressure actually to crush the bones of the foot. A more progressive variant, found in both the British Isles and France, consisted of a trio of upright wooden boards that splinted around and between the feet, fundamentally identical to the Chinese foot torture known as kia quen, and were tied in place by cords. Wedges were hammered between the boards and the feet to dislocate and crush the bones. Even ancient India saw the use of the kittee, a simplistic wooden press for squeezing feet. A prototype hailing from Autun, France, consisted of high boots of spongy, porous leather that were drawn over the feet and legs. Boiling water was poured over the boots, eventually soaking through the leather and eating the flesh away from the entrapped limbs. Lastly, oversized boots of iron or copper (often soldered in place on the floor) received the prisoner's bare feet as he lay helplessly bound and gagged in a chair. The boots were slowly filled with boiling water or oil, or even molten lead, to consume the feet and legs. One variant--applied in Ireland to the martyr Dermot O'Hurley--consisted of lightweight metal boots that were filled with cool water and heated with the feet inside over a fire until the water boiled aggressively.
A similar implement, the foot press, consisted of a pair of horizontal iron plates slowly tightened around the bare foot by means of a crank mechanism, squeezing the foot with sufficient force to pulverize the bones. Although it was quite standard to line the lower plate with ribs to prevent the foot from popping out of the grip of the instrument as it became sweatier, a crueler variant of this device—typically encountered in Nuremberg, Germany—lined the upper plate with hundreds of sharp spikes. A version from Venice, sometimes called the foot screw or toe breaker, connected the crank mechanism to a drill that slowly mutilated the foot by boring a hole through the center of the instep as the press was tightened. In the most extreme case, the press was tightened until the plates met, so grinding the foot bones to powder.
Medieval boots were built according to a wide array of architectures. One commonly encountered boot consisted fundamentally of a pair of upright parallel boards that splinted the toes. Turning the screw squeezed the toes between the boards, inflicting lateral pressure on the metatarsal heads and causing agony. This is the type of boot commonly associated with the torture of Esmeralda in Victor Hugo's Hunchback of Notre-Dame. The cruelty of the torture could be increased by spacing the toes apart with stiff wooden pegs. Various extensions of the instrument were designed to crush the ankle, calf, or knee in addition to its primary target, the instep. The toes often protruded from the front of the boot, facilitating the infliction of ancillary tortures, such as forcibly tearing the nails from the toes with red-hot pincers or exploring the delicate webbing between the toes with a red-hot iron probe. This type of boot, also called the brodequin, seems to have been the commonest torture device in France.
In The Big Book of Pain, Donnelly and Diehl present an ingeniously and sophisticated iron torture boot. The configurable device completely encloses the naked foot. The roomy toe box is filled with iron spikes, teeth, and burs. A vertical plate behind the prisoner's heel fits into a grooved track and can be forced forward by turning a wheel. The steadily increasing pressure first forces the toes against the spikes, mangling their flesh and crushing their bones. Under continued inexorable pressure, the bones of the instep eventually give way until the arch of the foot is shattered.