Many doctors will refer to a rotator cuff tear as a “full tear” or “partial tear.”

  • A full tear is a complete severing of the soft tissue.
  • A partial tear indicates some of the soft tissue is still intact. Partial tears of the rotator cuff are sometimes classified according to severity:
    • Grade 1 for tears less than 3 mm
    • Grade 2 for tears 3 mm to 6 mm
    • Grade 3 for those greater than 6 mm

Other doctors may simply categorize a tear based on whether the muscle or tendon is torn more than halfway through:

  • “High-grade” indicates a tear greater than 50% thickness
  • “Low-grade” indicates a tear less than 50% thickness

Before diagnosing a rotator cuff tear or estimating its severity, a doctor must rule out other possible causes of shoulder pain, such as shoulder bursitis (subacromial bursitis), cervical spine disease, and shoulder arthritis.

Diagnostic process for rotator cuff pain

The diagnostic process typically starts with a patient interview and physical exam, and may include medical imaging, such as x-ray, ultrasound or MRI.

  • Patient interview. The doctor will ask the patient about his or her history of pain with overhead activities, night pain, weakness and reduction of range of motion from pain.
  • Physical exam. The doctor will physically examine the rotator cuff (particularly the front of the shoulder, which is commonly affected). By testing rotator cuff muscles in isolation, and performing some stress maneuvers for impingement and instability, a doctor can frequently isolate rotator cuff injuries without the use of imaging tests.

    See Decompression Surgery for Shoulder Impingement

  • X-rays. Plain x-rays, also called radiographs, can help the doctor assess for arthritis of the shoulder, bone impingement, and calcific tendonitis, in which calcium deposits have formed in the tendons. With the exception of the latter, radiographs will not diagnose an injury to the rotator cuff itself, but they may show risk factors to degenerative tears or evidence of prior shoulder injury.
  • Ultrasound. Ultrasound is an increasingly utilized method for diagnosing rotator cuff injuries and other soft tissue injuries of the shoulders. Unlike X-rays, ultrasound allows the doctor to identify different soft tissues (e.g. muscles); it can be performed in the doctor’s office; and no radiation is delivered to the patient. Moreover, because ultrasound offers real-time imaging, the doctor can ask the patient to move his or her shoulder and observe the soft-tissue movements on screen, helping the doctor verify or rule out shoulder impingement issues.
  • MRI. MRI has been the gold standard for visualizing rotator cuff injuries because it provides a detailed, cross-sectional view of the shoulder that ultrasound cannot provide. However, MRI does not allow the doctor to observe soft tissue changes during shoulder movement. The patient must be completely still during this procedure, which takes approximately 30 minutes.

Depending on the patient’s symptoms and circumstances, a doctor may order medical imaging right away or may prescribe nonsurgical treatment and take a wait-and-see approach.

Dr. Michael Erickson is a sports medicine physician who provides care for adults and children. He also serves as the Sports Medicine Fellowship Director at Swedish Medical Center in Seattle, WA. Dr. Erickson's interests are concussion management and musculoskeletal diagnostic procedures. He is the Head Team Physician for all of Seattle University's varsity sport programs.