Why can astronomers see the spiral arm of the Andromeda galaxy more clearly than the spiral arms of the milky way galaxy?

It's to do with where you are trying to view from. We are inside the Milky Way Galaxy looking out whilst the Andromeda Galaxy is a distance and we are looking towards it. Imagine your are stood in a crowd of people it's difficult to work out the exact shape of the crowd however if you were in a helicopter looking down on it you could.