1. Disc shape, ideal, more common in development period.
2. The hemisphere (Venus type) is the most ideal and beautiful.
3. Cone is an ideal shape, but it may incline downward with the increase of age.
4. Flat, mostly thin.
5. Bird beak shape.
6. It is upturned, the muscles at the bottom are weak, and ribs can be seen in the chest.
7. Hooks and flat chests are common.
8. drooping, small.
9. It's turned up.