High Quality Content by WIKIPEDIA articles! The Sagittarius Arm (also known as Sagittarius-Carina Arm, labeled -I) is generally thought to be one of the spiral arms of our home galaxy, the Milky Way. Each spiral arm is a long, diffuse curving streamer of stars that radiates out from the galactic center. These gigantic structures are often composed of billions of stars, and Sagittarius is one of the largest arms in our galaxy. The Milky Way is a barred spiral galaxy, consisting of a central crossbar from which several spiral arms radiate outwards. The Sagittarius Arm's innermost end connects to one of the ends of this central bar, making it one of the two major spiral arms of the galaxy. The other large arm is the Cygnus Arm.