The Sagittarius-Carina Arm, sometimes merely referred to as the Sagittarius Arm, is one of the spiral arms of the Milky Way Galaxy. As its innermost end connects to the central bar of the galaxy, it is one of the two major arms of the Milky Way. The region of the Milky Way identified as the Carina Arm is actually a subsection of this galactic region.
During the Borg Invasion of 2381, the USS Aventine and USS Enterprise-E investigated a series of subspace tunnels centralized in the Azure Nebula. One of the tunnels exited the Aventine into the Delta Quadrant halfway between the Carina Arm and the Perseus Arm; another one stranded both vessels on the outer rim of the Carina Arm near the meridian between the Delta and Gamma Quadrants, where they faced a Hirogen fleet. (ST - Destiny novel: Mere Mortals)