It's a very important internal motion of the shoulder that allows the shoulder to move so far in so many directions. In fact of all the joints, the shoulder is the most mobile because of these extra or accessory motions.

The humeral head glides in five different directions: up (superior glide), down (inferior glide), away from the body (lateral glide), forward (anterior glide), and backward (posterior glide).

A decrease in any of these translations will affect your shoulder range of motion. Too much slide or glide increases the shoulder looseness or laxity. Excess joint laxity can lead to joint instability and dislocation.

One way to gauge how well you are doing after the type of injury and surgery you've had is to test joint accessory motions. This helps the doctor and therapist plan the right treatment for you.

Next time someone starts moving your shoulder this way, stop and ask them to explain what they are doing. Most healthcare providers are more than happy to help patients understand what they are doing and why they are doing it.