anterior spring and concealed tendons to simulate natural-looking movement. dubois parmlee – created prosthetic with a suction socket, polycentric knee, and multi-articulated foot. marcel desoutter & charles desoutter – first aluminium prosthesis henry heather bigg, and his son henry robert heather bigg, won the queen's command to provide "surgical appliances" to wounded soldiers after crimea war. they developed arms that allowed a double arm amputee to crochet, and a hand that felt natural to others based on ivory, felt and leather. at the end of world war ii, the nas (national academy of sciences) began to advocate better research and development of prosthetics. through government funding, a research and development program was developed within the army, navy, air force, and the veterans administration. lower extremity modern history an artificial limbs factory in 1941 after the second world war a team at the university of california, berkeley including james foort and c.w. radcliff helped to develop the quadrilateral socket by developing a jig fitting system for amputations above the knee. socket technology for lower extremity limbs saw a further revolution during the 1980s when john sabolich c.p.o., invented the contoured adducted trochanteric-controlled alignment method (catcam) socket, later to evolve into the sabolich socket. he followed the direction of ivan long and ossur christensen as they developed alternatives to the quadrilateral socket, which in turn followed the open ended plug socket, created from wood. the advancement was due to the difference in the socket to patient contact model. prior to this, sockets were made in the shape of a square shape with no specialized containment for muscular tissue. new designs thus help to lock in the bony anatomy, locking it into place and distributing the weight evenly over the existing limb as well as the musculature of the patient. ischial containment is well known and used today by many prosthetist to help in patient care. variations of the ischial containment socket thus exists and each socket is tailored to the specific needs of the patient. others who contributed to socket development and changes over the years include tim staats, chris hoyt, and frank gottschalk. gottschalk disputed the efficacy of the cat-cam socket- insisting the surgical procedure done by the amputation surgeon was most important to prepare the amputee for good use of a prosthesis of any type socket design. the first microprocessor-controlled prosthetic knees became available in the early 1990s. the intelligent prosthesis was the first commercially available microprocessor-controlled prosthetic knee. it was released by chas. a. blatchford & sons, ltd., of great britain, in 1993 and made walking with the prosthesis feel and look more natural. an improved version was released in 1995 by the name intelligent prosthesis plus. blatchford released another prosthesis, the adaptive prosthesis, in 1998. the adaptive prosthesis utilized hydraulic controls, pneumatic controls, and a microprocessor to provide the amputee with a gait that was more responsive to changes in walking speed. cost analysis reveals that a sophisticated above-knee prosthesis will be about $1 million in 45 years, given only annual cost of living adjustments. in 2019, a project under at2030 was launched in which bespoke sockets are made using a thermoplastic, rather than through a plaster cast. this is faster to do and significantly less expensive. the sockets were called amparo confidence sockets. upper extremity modern history in 2005, darpa started the revolutionizing prosthetics program. patient procedure a prosthesis is a functional replacement for an amputated or congenitally malformed or missing limb. prosthetists are responsible for the prescription, design, and management of a prosthetic device. in most cases, the prosthetist begins by taking a plaster cast of the patient's affected limb. lightweight, high-strength thermoplastics are custom-formed to this model of the patient. cutting-edge materials such as carbon fiber, titanium and kevlar provide strength and durability while making the new prosthesis lighter. more sophisticated prostheses are equipped with advanced electronics, providing additional stability and control. current technology and manufacturing knee prosthesis manufactured using worknc computer aided manufacturing software over the years, there have been advancements in artificial limbs. new plastics and other materials, such as carbon fiber, have allowed artificial limbs to be stronger and lighter, limiting the amount of extra energy necessary to operate the limb. this is especially important for trans-femoral amputees. additional materials have allowed artificial limbs to look much more realistic, which is important to trans-radial and transhumeral amputees because they are more likely to have the artificial limb exposed. manufacturing a prosthetic finger in addition to new materials, the use of electronics has become very common in artificial limbs. myoelectric limbs, which control the limbs by converting muscle movements to electrical signals, have become much more common than cable operated limbs. myoelectric signals are picked up by electrodes, the signal gets integrated and once it exceeds a certain threshold, the prosthetic limb control signal is triggered which is why inherently, all myoelectric controls lag. conversely, cable control is immediate and physical, and through that offers a certain degree of direct force feedback that myoelectric control does not. computers are also used extensively in the manufacturing of limbs. computer aided design and computer aided manufacturing are often used to assist in the design and manufacture of artificial limbs. most modern artificial limbs are attached to the residual limb (stump) of the amputee by belts and cuffs or by suction. the residual limb either directly fits into a socket on the prosthetic, or—more commonly today—a liner is used that then is fixed to the socket either by vacuum (suction sockets) or a pin lock. liners are soft and by that, they can create a far better suction fit than hard sockets. silicone liners can be obtained in standard sizes, mostly with a circular (round) cross section, but for any other residual limb shape, custom liners can be made. the socket is custom made to fit the residual limb and to distribute the forces of the artificial limb across the area of the residual limb (rather than just one small spot), which helps reduce wear on the residual limb. production of prosthetic socket the production of a prosthetic socket begins with capturing the geometry of the residual limb, this process is called shape capture. the goal of this process is to create an accurate representation of the residual limb, which is critical to achieve good socket fit. the custom socket is created by taking a plaster cast of the residual limb or, more commonly today, of the liner worn over their residual limb, and then making a mold from the plaster cast. the commonly used compound is called plaster of paris. in recent years, various digital shape capture systems have been developed which can be input directly to a computer allowing for a more sophisticated design. in general, the shape capturing process begins with the digital acquisition of three-dimensional (3d) geometric data from the amputee's residual limb. data are acquired with either a probe, laser scanner, structured light scanner, or a photographic-based 3d scanning system. after shape capture, the second phase of the socket production is called rectification, which is the process of modifying the model of the residual limb by adding volume to bony prominence and potential pressure points and remove volume from load bearing area. this can be done manually by adding or removing plaster to the positive model, or virtually by manipulating the computerized model in the software. lastly, the fabrication of the prosthetic socket begins once the model has been rectified and finalized. the prosthetists would wrap the positive model with a semi-molten plastic sheet or carbon fiber coated with epoxy resin to construct the prosthetic socket. for the computerized model, it can be 3d printed using a various of material with different flexibility and mechanical strength. optimal socket fit between the residual limb and socket is critical to the function and usage of the entire prosthesis. if the fit between the residual limb and socket attachment is too loose, this will reduce the area of contact between the residual limb and socket or liner, and increase pockets between residual limb skin and socket or liner. pressure then is higher, which can be painful. air pockets can allow sweat to accumulate that can soften the skin. ultimately, this is a frequent cause for itchy skin rashes. over time, this can lead to breakdown of the skin. on the other hand, a very tight fit may excessively increase the interface pressures that may also lead to skin breakdown after prolonged use. artificial limbs are typically manufactured using the following steps: measurement of the residual limb measurement of the body to determine the size required for the artificial limb fitting of a silicone liner creation of a model of the liner worn over the residual limb formation of thermoplastic sheet around the model – this is then used to test the fit of the prosthetic formation of permanent socket formation of plastic parts of the artificial limb – different methods are used, including vacuum forming and injection molding creation of metal parts of the artificial limb using die casting assembly of entire limb body-powered arms current technology allows body-powered arms to weigh around one-half to one-third of what a myoelectric arm does. sockets current body-powered arms contain sockets that are built from hard epoxy or carbon fiber. these sockets or "interfaces" can be made more comfortable by lining them with a softer, compressible foam material that provides padding for the bone prominences. a self-suspending or supra-condylar socket design is useful for those with short to mid-range below elbow absence. longer limbs may require the use of a locking roll-on type inner liner or more complex harnessing to help augment suspension. wrists wrist units are either screw-on connectors featuring the unf 1/2-20 thread (usa) or quick-release connector, of which there are different models. voluntary opening and voluntary closing two types of body-powered systems exist, voluntary opening "pull to open" and voluntary closing "pull to close". virtually all "split hook" prostheses operate with a voluntary opening type system. more modern "prehensors" called grips utilize voluntary closing systems. the differences are significant. users of voluntary opening systems rely on elastic bands or springs for gripping force, while users of voluntary closing systems rely on their own body power and energy to create gripping force. voluntary closing users can generate prehension forces equivalent to the normal hand, up to or exceeding one hundred pounds. voluntary closing grips require constant tension to grip, like a human hand, and in that property, they do come closer to matching human hand performance. voluntary opening split hook users are limited to forces their rubber or springs can generate which usually is below 20 pounds. feedback an additional difference exists in the biofeedback created that allows the user to "feel" what is being held. voluntary opening systems once engaged provide the holding force so that they operate like a passive vice at the end of the arm. no gripping feedback is provided once the hook has closed around the object being held. voluntary closing systems provide directly proportional control and biofeedback so that the user can feel how much force that they are applying. in 1997, the colombian prof. álvaro ríos poveda, a researcher in bionics in latin america, developed an upper limb and hand prosthesis with sensory feedback. this technology allows amputee patients to handle prosthetic hand systems in a more natural way. a recent study showed that by stimulating the median and ulnar nerves, according to the information provided by the artificial sensors from a hand prosthesis, physiologically appropriate (near-natural) sensory information could be provided to an amputee. this feedback enabled the participant to effectively modulate the grasping force of the prosthesis with no visual or auditory feedback. in february 2013, researchers from école polytechnique fédérale de lausanne in switzerland and the scuola superiore sant'anna in italy, implanted electrodes into an amputee's arm, which gave the patient sensory feedback and allowed for real time control of the prosthetic. with wires linked to nerves in his upper arm, the danish patient was able to handle objects and instantly receive a sense of touch through the special artificial hand that was created by silvestro micera and researchers both in switzerland and italy. in july 2019, this technology was expanded on even further by researchers from the university of utah, led by