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Intersecting and Parallel Lines

Define and identify intersecting and parallel lines.

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A Road Map to Healing

Credit: Kristopher Radder/U.S. Navy
Source: http://www.flickr.com/photos/56594044@N06/7773528446/
License: CC BY-NC 3.0

Surgery requires many specialized tools and instruments, such as those pictured above. But do you know how parallel lines are used in an operating room?

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In 1861, Karl Langer, an Austrian anatomist, discovered that by drawing lines in a specific way on a map of the human body, the lines would be parallel to the underlying muscle fibers. Although Langer is credited with this discovery, he acknowledged that French surgeon Baron Dupuytren was the first to notice this. You can see Langer's lines drawn on the image of the head and neck below.

Credit: Laura Guerin
Source: CK-12 Foundation
License: CC BY-NC 3.0

How are these lines important? Langer's lines gave him a guideline before surgery—a trail to follow as he worked. Today, surgeons, especially those working in cosmetic or forensic surgery, still use Langer's lines as a blueprint to help them understand where the muscle fibers are in the body. This discovery has led to the development of specific surgical techniques and has helped surgeons locate nerves and organs for medical procedures. It has also been found that incisions made parallel to Langer's lines may heal better.

Watch this video to see more examples of parallel and perpendicular lines in the real world: http://www.youtube.com/watch?v=vnnwfcDcNlY

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Play the game at the first website below to practice recognizing parallel lines. Then use the virtual geoboard at the next link to explore parallel lines and other shapes too!



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Image Attributions

  1. [1]^ Credit: Kristopher Radder/U.S. Navy; Source: http://www.flickr.com/photos/56594044@N06/7773528446/; License: CC BY-NC 3.0
  2. [2]^ Credit: Laura Guerin; Source: CK-12 Foundation; License: CC BY-NC 3.0

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