There’s something undeniably beautiful about prosthetic limbs, designed to echo the physical grace and mechanical engineering of the human body. For most people, these objects elicit some combination of squeamish discomfort and utmost respect. But far fewer of us connect those feelings to the untold generations of battle-scarred amputees whose sacrifices made prosthetics a public priority.

“Patients even have doctors sign non-disclosure forms to protect potential patents.”

“You hate to think that war is what drives technology, but it does,” says Kevin Carroll, the Vice President of Prosthetics for Hanger, a major artificial-limb producer founded just after the Civil War. Historically, the impulse to create functional replacement limbs has grown in parallel with the number of living amputees, whose ranks ballooned following periods of military conflict, especially the American Civil War and World War I. Such episodes of violence provided the impetus for doctors and scientists to study how the human body copes with physical damage, and how we might repair it.

Today, double amputees regularly win gold medals at the Paralympics, and computer-based technologies allow replacement limbs to translate signals from the human brain into motion. But it’s been a long and violent haul from the wooden “peg-leg” days when amputees were pitied, ignored, or actually destined to die because of limited medical care.

Though amputation was one of the first recorded surgeries, mentioned in the Hippocratic treatise “On Joints” around the 4th century BC, the procedure really became a viable option after major improvements were made in blood-loss prevention during the 15th and 16th centuries. Doctors began working with ligatures to seal off individual blood vessels and eventually used tight tourniquets around entire appendages to slow blood flow.

However, amputation was still only sought for patients whose life was already at stake due to severe infection or injury, particularly because the consequences of surgery were frequently fatal anyway. “The control of a number of associated factors–blood loss, pain, and infection prevention–has been key to greatly improving the survival chances of the amputee,” says Stewart Emmens, the curator of Community Health at the Science Museum in London. “Then, as now, the procedure was often viewed as a failure of treatment.”

Physicians like Ambroise Paré, the official barber-surgeon for the Kings of France during the 16th century, noted the unfortunate effects of prevailing surgical methods and sought better ways to heal patients. Paré was especially interested in battlefield wounds, and his first published book covered techniques to treat firearm injuries, helping to expose the problems with commonly used cauterization methods.

Other advancements, like the capacity to amputate in specific locations along an appendage, also made it possible for survivors to live longer with fewer complications. But the chance for amputees to regain a sense of normalcy typically depended on the quality of artificial limbs available. Though articulated limbs were being developed around the same time, like the famous iron arm designed for Gottfried “Götz” von Berlichingen with various locking hand positions, these were exclusively made for affluent individuals.

A real breakthrough in prosthetic limb mechanics came in the form of James Potts’ “Anglesey” leg design around 1800, a style popularized by the Marquess of Anglesey after he was injured in the Battle of Waterloo in 1815 . Later dubbed “the Clapper” for the clicking sound made by its articulated parts, Potts’ creation relied on cat-gut tendons to hinge at the knee and ankle, simulating a walking motion when the toe was lifted. The design was later improved by Benjamin Palmer with his so-called “American leg,” which incorporated a heel spring in 1846 and was continuously produced through World War I.

Still, until the mid-20th century, such replacement limbs were financially inaccessible to the many working class individuals who needed them. “A Victorian agricultural laborer who lost his lower arm in an accident was probably more likely to get the local blacksmith to make a hooked prosthesis for him than to check the catalog of the nearest limb manufacturer,” says Emmens. “These were relatively expensive items, and given that any gripping, flexing, or thumb-to-finger movements would depend on a system of joints, cords, and shoulder harnesses, they were not necessarily that practical for working people either.”

Whether or not they could afford a newfangled arm or leg, amputees got on with their lives, learning to cope with their disabilities and inventing their own solutions. Some became so comfortable using temporary limb replacements that they never attempted to find a fully functioning prosthetic. Others fashioned their own devices from available materials, making necessary repairs as time went on.

In America, the major pressure to improve amputee rehabilitation came along with the Civil War, when novel firearms like the repeating rifle left around 35,000 survivors in need of new limbs. Following the war, public funds were devoted to developing and purchasing these prosthetics; in 1866, the State of Mississippi spent more than half its yearly budget providing veterans with artificial limbs. Entrepreneurs, many of them young veterans themselves, recognized the opportunity to create improved mechanical devices that would allow amputees to enjoy more normal lives.

James Edward Hanger was one of these young soldiers, an 18-year-old engineering student at Washington College who left school to join Confederate forces in a small West Virginia town. While waiting for the troops to return from a nearby village, a surprise attack by the Union army sent a cannonball ricocheting into the stable where Hanger was camped, smashing his left leg. Hours later, Hanger was discovered by the Union forces and an above-the-knee amputation was performed. The surgery became the first recorded amputation of the Civil War.

While recovering at his parents’ Virginia home, Hanger worked to improve the standard-issue replacement leg he was given by the Army, a solid piece of wood that made walking difficult and noisy. Within a few months, he created a prototype that allowed for a smoother, quieter walking motion. Though the original patent is lost, Hanger’s adjustments to the generic leg style included better hinging and flexing abilities using rust-proof levers and rubber pads.

“The function of a prosthetic limb will always endow it with a certain magic few other man-made objects possess.”

Hanger immediately wrote to William Carrington, secretary of the Association for the Relief of Maimed Soldiers, to secure Carrington’s endorsement and the business of his veterans group. A few years later, the Virginia legislature created a $20,000 fund to purchase prosthetics for the state’s wounded veterans, providing even more business for Hanger. By 1890, Hanger had relocated his headquarters to Washington, D.C., and opened satellite offices in four other U.S. cities.

Despite innovators like Hanger, the best prosthetics were still out of reach for most ordinary people, whether veterans or not. These inventive devices were tailored specifically to suit specific tasks or lifestyles, like the special hand with an octave finger-spread and padded fingers created for a British concert pianist. It would require the violence of another major war to make custom limbs a reality for more amputees.

With the onset of World War I, the need for prosthetics escalated exponentially. As this was the first war in which industrialized weaponry like machine guns created more bodily harm than infection or disease, an extraordinary number of soldiers survived with severe injuries.

This new kind of warfare “produced new levels, new degrees of wounding,” explains Emmens. “Bodies were ripped apart by explosives; arms and legs were simply blasted off.” But countless soldiers lost their limbs through surgical intervention. “Much of the war–particularly on the Western Front–was essentially fought on well-manured farmland, and explosive weaponry could carry these highly infectious materials deep into complex, gaping wounds,” says Emmens. Amputation was frequently used in situations that normally wouldn’t require surgery, simply to avoid the threat of serious infection.

Prosthetic manufacturing boomed again, though the locus of limb development shifted overseas. In Great Britain veterans were entitled to free limbs beginning with the Napoleonic Wars of the early 19th century, yet Emmens explains that during World War I, “the existing systems of medical care were soon exposed as inadequate to deal with the sheer scale of casualties.” By the end of the war, there were an estimated 41,000 amputees in Britain alone.

Besides the overwhelming demand, shoddy fittings and unhelpful instructions meant that even available prosthetics sometimes went unused. “Many arm amputees simply stopped wearing their uncomfortable devices, put them in a cupboard somewhere, and never used them again, while some leg amputees found life easier with crutches than wearing uncomfortable, heavy prosthetic legs,” says Emmens.

In 1920, an article in The Times of London stated that “next to the loss of life, the sacrifice of a limb is the greatest sacrifice that a man can make for his country.” But the British government wasn’t prepared to assist the flood of amputees, even during the early months of the war, and several wealthy patrons quickly stepped in to establish private facilities for soldier rehabilitation. One of the most significant was Queen Mary’s Hospital, which focused on veterans who had lost limbs; this repurposed country home in southwest London soon became a global center for artificial limb design and fitting.

American manufacturers like Hanger and Rowley set up workshops at Queen Mary’s Hospital to churn out custom limbs and assist with fittings and training. Though only a handful of artificial limb designs came from England prior to the war, by 1918, several hundred British patent applications had been submitted. When the influx of new amputees finally slowed during the 1920s, manufacturers began focusing on improving their best products rather than providing as many limbs as possible.

Postwar designs incorporated a variety of recently patented innovations. In 1912, D.W. Dorrance had created a famous split-hook hand attachment for artificial arms, which allowed users to grip objects and perform daily tasks in a much easier manner. The following year, aviator and amputee Marcel Desoutter had worked with his brother Charles, an engineer, to develop a prosthetic leg made from a lightweight aluminum alloy.

“In Germany, much was made of returning wartime amputees to productivity, and industrial giants like Siemens were at the forefront of developing and introducing the means to do this,” says Emmens. Siemens designed a variety of “workers arms” which sacrificed aesthetic appeal to focus on function, designed to accommodate a range of workplace tools. Products like these led a shift away from traditional materials like wood and leather towards lighter metals and plastics.

In a 1929 article on the evolution of the artificial limb, American doctor J. Duffy Hancock wrote that “putting a cripple back to work ranks next to saving a life.” Though harsh-sounding, Hancock’s remark captures a powerful sentiment: If we save someone’s life, they should be able to live it as fully as possible. And artificial limbs provided that key, minimizing the stigma, isolation, and lifestyle limitations that often came with amputation.

Today, the power of prosthetics is more visible than ever before, particularly among young veterans recovering from injuries sustained in the Middle East. Kevin Carroll describes a recent outing with a group of veterans at a rehabilitation center in San Diego, California. “As we’re walking up the street, one of the guys climbed up on a tall ledge and jumped right off,” says Carroll. “Here’s a guy with both of his legs cut above the knee, and he comes right down on the prosthetics. Why would you want to do that? Well, because you’re a young kid and you want to continue to act like one.”

As veterans of the wars in Iraq and Afghanistan continue to flood VA hospitals across the country, their treatment helps to push prosthetic technology once again. Despite the fact that diabetes is the number one cause for limb amputation in the U.S. today, the veteran population still drives many advances in the field, as they willingly test the latest devices and generate their own ideas, too. Carroll says that some patients even have their doctors sign non-disclosure forms to protect potential patents.

Special limbs are also now created for extreme physical activities, such as specific legs tailored for sprinting versus long distance running. These products have enabled such incredible performances that sporting authorities are questioning whether professional athletes like the South African runner Oscar Pistorius, who happens to be missing both legs, may actually be given an unfair advantage.

High-performance limbs also benefit those outside the world of professional sports, as their components are adapted for ordinary prosthetics. “It reminds me of NASCAR,” Carroll says. “You see those guys racing around the track at 200 miles an hour, and in the not-too-far-away future, the technologies in their cars will be in our regular cars. It’s the same way with prosthetics, with these high-performance feet that these young men and women are pushing to the limits. Grandma may very well be walking across the floor on them next year.”

Some of the more recent prosthetic innovations include new silicone materials used to improve socket fit and energy-storing devices made from carbon-fiber composites. Carroll even worked to develop a prosthetic tail for an injured dolphin using a gel sleeve, which was modified to help human patients with fitting issues.

Possibly the most exciting advancements are those that incorporate microprocessor technologies. These tiny computers register the minute details of ordinary movements to prevent limbs from buckling and anticipate the user’s next move. “Even two years ago, to have somebody walk naturally step over step upstairs on prosthetics was difficult, a chore,” says Carroll, yet today he works with double-amputees who handle inclines easily, thanks to implanted microprocessors.

Regardless of this shifting technology, patients still develop the strong emotional connections to modern limbs they did centuries ago. The function of a prosthetic limb—to replace a part of the human body—will always endow it with a certain magic few other man-made objects possess.

“There’s an incredible bond that takes place between a person and their prosthesis,” says Carroll. “If I’m taking that prosthetic device out of the room and bringing it back to a laboratory to check it out, they’re watching it as if it’s part of their body leaving the room. They’re watching how I pick it up, how I hold it, am I being gentle with it. And it makes you realize this is their lifeline.”