Medical Definition of dorsiflexion. : flexion in a dorsal direction; especially : flexion of the foot in an upward directionâcompare plantar flexion.
Willis Tower. The Willis Tower, built as and still commonly referred to as Sears Tower, is a 108-story, 1,450-foot (442.1 m) skyscraper in Chicago, Illinois, United States.
One World Trade Center will be the tallest skyscraper in the U.S. at 1,776 feet when it opens this year. The Willis Tower in Chicago stands 1,451 feet, while the world's tallest building is the Burj Khalifa in Dubai at 2,717 feet.