Shoulder Impingement

The shoulder is one of the most mobile joints in the body, allowing a wide range of arm movement. This mobility comes from the interaction of bones, muscles, tendons, and soft tissue structures working in harmony.

• • Bones: The shoulder joint involves three bones:
    • • Humerus – the upper arm bone
      • Scapula – the shoulder blade
      • Clavicle – the collarbone

• Joints: The main joint of the shoulder is the glenohumeral joint, where the head of the humerus fits into the shallow socket of the scapula called the glenoid. This ball-and-socket joint allows for rotation and lifting. Other joints include the acromioclavicular (AC) joint where the clavicle meets the acromion, and the sternoclavicular joint at the chest.

• Rotator Cuff: The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint:
  • Supraspinatus
  • Infraspinatus
  • Teres Minor
  • Subscapularis

  These muscles stabilize the joint and allow you to lift and rotate your arm.

• Bursa: A fluid-filled sac called the subacromial bursa sits between the rotator cuff and the acromion. It cushions movement and reduces friction during arm elevation.

Understanding this anatomy is essential when exploring shoulder conditions like shoulder impingement, rotator cuff tendinitis, or adhesive capsulitis, each of which affects different parts of this complex system.

Patients often hear terms like “tendinitis,” “impingement,” or “rotator cuff tear” and assume they are interchangeable. While these conditions may overlap, they have distinct causes and implications:

• Rotator Cuff Tendinitis: Inflammation of the rotator cuff tendons—usually due to repetitive strain. Pain is typically gradual and worsens with overhead activity.
• Rotator Cuff Tear: A partial or complete rupture of one or more rotator cuff tendons. Often results from trauma or degeneration and causes noticeable weakness.
• Rotator Cuff Syndrome: A broad label for dysfunction in the rotator cuff, encompassing tendinitis, tears, or impingement symptoms.
• Shoulder Impingement: A mechanical narrowing of space between the rotator cuff and acromion that compresses soft tissue during motion.
• Adhesive Capsulitis (Frozen Shoulder): Thickening and contracture of the joint capsule, leading to severe stiffness and restricted range of motion.

Continue reading below for a detailed table that compares these common shoulder problems side-by-side.

Still unsure which shoulder condition is causing your symptoms? Visit our Shoulder Pain Resource Center or learn more at Mayo Clinic.

Shoulder impingement and rotator cuff irritation often cause localized swelling and tenderness in the front of the shoulder. You may experience pain and stiffness when lifting your arm or lowering it from an elevated position.

Early symptoms:

• Minor pain both with activity and at rest
• Pain radiating from the front of the shoulder to the side of the arm
• Sudden discomfort during lifting or reaching
• Overhead athletes may have pain during throwing or serving

Advanced symptoms:

• Persistent pain at night, especially when lying on the affected side
• Loss of strength and shoulder range of motion
• Difficulty with daily tasks—like buttoning a shirt or reaching behind the back

In cases of acute shoulder impingement, pain may be intense, and all movement can become severely restricted.

Medical History and Physical Examination

After reviewing your symptoms and health history, your doctor will examine your shoulder for tenderness, deformity, or loss of motion. You’ll be asked to move your arm in different directions, and your shoulder strength will be tested.

Shoulder impingement tests—such as the Neer and Hawkins-Kennedy signs—may be performed to confirm diagnosis. Your doctor may also examine your neck to rule out referred pain from a pinched nerve or cervical radiculopathy.

Imaging Tests

Additional studies may help confirm a diagnosis:

• X-rays: While X-rays don’t show soft tissues like the rotator cuff, they can reveal bone spurs or acromion abnormalities. An outlet view may show impingement-related narrowing.
• MRI or ultrasound: These advanced studies provide better images of the rotator cuff, subacromial bursa, and surrounding structures. They may show signs of inflammation, thickening, or even partial tears.

For more on shoulder impingement imaging, visit this PubMed imaging overview.

The main goals of treatment for shoulder impingement are to reduce inflammation, restore shoulder mobility, and improve function. Your doctor will consider your age, activity level, and overall health when developing a plan.

Nonsurgical Treatment

• Rest: Avoid overhead activities that worsen your pain.
• NSAIDs: Medications such as ibuprofen or naproxen reduce swelling and discomfort.
• Physical therapy: Focuses on restoring flexibility and shoulder biomechanics. Posterior capsule stretches can be particularly effective for shoulder impingement.
• Steroid injection: If conservative care fails, a cortisone injection into the subacromial space may reduce inflammation and pain quickly.

Many patients with shoulder impingement improve with these treatments over several weeks to months.

Surgical Treatment

If symptoms persist despite conservative measures, your doctor may suggest surgery to relieve impingement by increasing the subacromial space.

• Arthroscopic technique: Small incisions allow for removal of inflamed tissue and bony spurs via a scope. This minimally invasive option is often preferred.
• Open technique: Used in more complex cases, it involves a small incision to directly access the impinged tissue and perform acromioplasty if needed.
• Rehabilitation: After surgery, you’ll begin physical therapy to restore range of motion and strength. Most patients recover fully in 2 to 4 months, though healing may take up to a year.

For more details on shoulder impingement treatment options, see the AAOS guide to shoulder impingement.

What is shoulder impingement?

Shoulder impingement occurs when the tendons of the rotator cuff become compressed or pinched under the acromion—the bony part of your shoulder blade—leading to pain, especially with overhead movement.

How do I know if I have shoulder impingement or a rotator cuff tear?

Impingement typically causes pain during movement but preserved strength. A rotator cuff tear often leads to weakness, especially when lifting the arm. Your provider may recommend imaging to confirm the diagnosis.

Can shoulder impingement heal on its own?

Mild cases can improve with rest, activity modification, physical therapy, and anti-inflammatory medications. Persistent or severe cases may require injections or, rarely, surgery.

What exercises should I avoid with shoulder impingement?

Avoid repetitive overhead motions, heavy lifting above shoulder height, and exercises that aggravate pain such as upright rows or behind-the-neck presses—unless advised by a medical provider or physical therapist.

When should I consider surgery for shoulder impingement?

If symptoms persist for more than 3–6 months despite conservative treatment—including physical therapy and steroid injections—your doctor may discuss minimally invasive surgical options like subacromial decompression.