The spiral galaxy, NGC 4622 (also called backward galaxy), lies approx. 111 million light years away from Earth in the constellation Centaurus. NGC 4622 is an example of a galaxy with leading spiral arms. In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation. In NGC 4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation. This may be the result of a gravitational interaction between NGC 4622 and another galaxy or the result of a merger between NGC 4622 and a smaller object.
NGC 4622 also has a single inner trailing spiral arm.Although it was originally suspected that the inner spiral arm was a leading arm, the observations that established that the outer arms were leading also established that the inner arm was trailing.