Go behind the scenes at a factory that makes top-of-the-line artificial legs that contain hydraulics, brakes, microchips, and miniature motors.
", "is_us_only": "false", "title": "I Didn't Know That: Prosthetic Leg", "url": "http://video.nationalgeographic.com/video/science/health-human-body-sci/human-body/idkt-prosthetic-leg/", "country_code_deny_list": [], "allowUserEmbed": "True", "related": { "link": [ { "url": "http://science.nationalgeographic.com/science/", "name": "More About Science" } ] }, "credit": "National Geographic", "smil": "http://video.nationalgeographic.com/video/player/data/xml/idkt-prosthetic-leg.smil", "country_code_allow_list": [], "HTML5src": "/video/player/media-mp4/idkt-prosthetic-leg/mp4/variant-playlist.m3u8", "still": "http://video.nationalgeographic.com/exposure/core_media/ngphoto/image/61044_0_616x346.jpg", "transcript": "This is how a company in Basingstoke, Hampshire makes prosthetic legs.
They start at the bottom.\u00a0 The chemicals isocyanate and polyol are mixed together to make a rubber compound which is injected into a mold.\u00a0 One minute later a hard foot appears.\u00a0 Nine different sizes are available.
Next the shin is manufactured from carbon fiber, the kind of stuff you normally find on super cars.
After it's been laid out the sheet is baked under immense pressure for 90 minutes.\u00a0 This compresses the layers of carbon fiber into a thin light but immensely strong structure.
Next, come the joints.\u00a0 This is an ankle.\u00a0 Strength is crucial so it's machined from a solid block of aluminum.\u00a0 This is a five axis machining center, one of only two in the UK.\u00a0 The other belongs to a leading formula one team.\u00a0 It cuts out the ankle joint while fluid keeps the blades the cool.\u00a0 From raw aluminum to finished joint.
The component parts of the joint are then assembled.\u00a0 If the limb is designed for very active use then the design is incredibly complex.
This top of the range knee will take two days to build and contains hydraulics, brakes, micro-chips and even miniature motors.\u00a0 They all make the action and re-action of the joint as natural and stable as possible.
Finally the socket has to be manufactured - the bits that connects all this high tech wizardry to the patient.\u00a0 The hospital simply provides a digital map of the stump from which the foam caste can be produced.\u00a0 A hot plastic film is then draped over it and then vacuum packed against the contours.
A perfect fit every time.\u00a0 And for those who don't wear trousers; here's where they make the skin.\u00a0 It's a silicon compound available in 8 different shades and carefully tailored to mask the joins.\u00a0 Add in some padding and you'd never know the difference.
", "id": "idkt-prosthetic-leg" } }