When it comes down to structure than our galactic home is like a spiral galaxy. A glimpse up at the night sky exposes a wide band of powerful light. Ancients described this band as a river and a path. Milky Way is a barred spiral galaxy and it is about 100,000 light years across.
If you take a look from top on the Milky Way Galaxy than you will see arms and recent research shows that the Milky Way Galaxy has four spiral arms (as you can see in the above image). We cannot take a real picture of the Milky Way from above because we are inside of it and using our recent technology we cannot get out of it. So wherever on the internet or any other place you see a picture of the Milky Way Galaxy then keep in mind that it is a picture of some another spiral galaxy, or the interpretation of a talented artist. The central bulge of the Milky Way Galaxy has a diameter of about 12000 light years. The Milky Way Galaxy has a crown of dark matter that makes up over 90% of its total mass. The crown of dark matter is actually undetectable, however, we know it exists by running some simulations of what the Milky Way would look like and how fast stars orbit inside the galaxy. The heavier it will be the stars should faster orbit.