Ultrasound can show many aspects of the soft tissues around the shoulder. It will show if there's any fluid within the tendons, the size and shape of bursae, and any tears in the tendons. By moving the arm during the test, the doctor can see if a tendon is partially or fully torn.

The image also shows if a torn tendon has drawn back into the muscle belly, called retraction. Knowing this helps the doctor plan treatment. The condition of the joint isn't as clear. Ultrasound doesn't show tears in the joint cartilage or the rim around the shoulder joint. MRI may be needed to see this kind of damage. X-ray may be better for seeing arthritic changes in the joint.