The bridge pose is used when you are coming out of the shoulder stand. You must have a flexible back to complete it safely. This is one of a set of yoga moves that if you do not have the proper spinal flexibility, it can also be achieved if you are willing to practice.
The Plough Yoga Pose
In order to do these types of yoga moves correctly, you need to use the muscle tone and flexibility that you developed learning other poses, like the shoulder stand. If you practice, you will be able to go in and out of this pose easily.
Flexibility is required for this pose and you may find it very difficult, if not impossible to reach your toes. Your goal is to be able to hold your toes in your hands. The more often you attempt these types of yoga moves, the more you will see an increase in your flexibility.
The Fish Yoga Pose
This is one of the yoga moves that will require you to use patience to complete it correctly. You must use care not to strain your neck or back. It can also take months to perfect this pose.
This is definitely one of the more difficult yoga moves, but is often the recommended pose for relieving constipation, pain, and also for help to relieve some menstrual irregularities.
The difficulty in this pose is not the ability to do the pose, but to hold it for an extended period of time. It is best to try to hold this pose for a minute or longer, but it can be very difficult if your back is not strong enough.
This is one of the yoga moves most people think of when they are referring to a "yoga pretzel." It is very difficult to get into and even more difficult to hold.
The Half Spinal Twist Yoga Pose
This pose will stretch almost every muscle in your body. It is difficult to get into and difficult to hold. However, this pose is one of the best for helping to remove muscular aches and pains, if it is performed correctly.
The Crow Yoga Pose
This is a pose that resembles what some people would do to attempt a handstand. However, you do not put your feet up and your head is lifted and facing forward. It is in a set of yoga moves that is almost exclusively used for very advanced students.
This pose requires very flexible back and limber legs. You will be touching your head to your shin when you have mastered one of these difficult yoga moves.
Resource from: http://www.healthyoga.com