Understanding Shoulder Anatomy

The shoulder is one of the most mobile joints in the body. It is made up of three bones:

• The humerus (upper arm bone)
• The scapula (shoulder blade)
• The clavicle (collarbone)

These bones form a ball-and-socket joint known as the glenohumeral joint. The joint is supported by a group of muscles and tendons called the rotator cuff, which stabilizes the shoulder and allows you to lift and rotate your arm.

Above the rotator cuff tendons is a bony structure on the shoulder blade called the acromion. Between the rotator cuff and the acromion is a fluid-filled sac called the subacromial bursa. Bursae are small fluid-filled sacs that cushion and protect joints. The shoulder bursae, including the subacromial bursa, reduce friction and allow the tendons to glide smoothly when the arm moves.

When the space between the acromion and the rotator cuff narrows, the tendons and bursa can become compressed. This leads to inflammation and pain, commonly referred to as shoulder impingement syndrome or subacromial bursitis.

What Is Shoulder Impingement?

Shoulder impingement occurs when the rotator cuff tendons and bursa become pinched between the acromion and the head of the humerus. This compression can irritate the soft tissues, cause inflammation and discomfort when lifting or rotating the arm.

Common symptoms of shoulder impingement include shoulder pain, stiffness, tenderness and weakness. As swelling and thickening of the tendons and bursa develop, they occupy more space within the shoulder joint, worsening the compression and inflammation.

Over time, untreated impingement can lead to additional problems such as:

• Rotator cuff tendinitis
• Shoulder bursitis
• Partial or full rotator cuff tears

Early diagnosis and treatment can help prevent these complications.

What Is Shoulder Bursitis?

Shoulder bursitis occurs when the subacromial bursa becomes inflamed. The bursa normally acts as a cushion that allows smooth movement between bones, tendons and muscles.

Symptoms of shoulder bursitis often include shoulder pain that may develop suddenly or gradually, along with a dull ache that can become sharp when lifting the arm.

When the bursa becomes irritated due to repetitive motion, injury or underlying shoulder conditions, it can swell and cause pain during movement. Bursitis often develops alongside shoulder impingement because the same mechanical compression that irritates the rotator cuff tendons can also inflame the bursa.

In rare cases, bursitis may become infected. Infected bursitis can cause warmth, redness, tenderness, fever and other signs of illness and requires prompt medical evaluation.

Causes of Shoulder Impingement and Bursitis

Injuries and overuse of the shoulder are the most common causes of bursitis and impingement.

Several factors can contribute to shoulder impingement and bursitis, including:

• Acute injuries such as sports injuries or trauma
• Repetitive movements that overuse the shoulder
• Structural issues within the shoulder joint
• Underlying inflammatory conditions

Repetitive Overhead Activities

Repetitive arm movements can place stress on the rotator cuff and surrounding tissues. This is common in sports and occupations involving overhead motion.

Examples include:

• Swimming
• Tennis
• Baseball or throwing sports
• Weightlifting
• Painting
• Carpentry
• Construction work

Overuse and Muscle Imbalance

Repeated shoulder motion without adequate strength or conditioning can lead to inflammation and mechanical irritation within the joint.

Aging and Degeneration

As people age, tendons become less flexible and more prone to irritation or injury. Degenerative changes can narrow the space within the shoulder joint, increasing the risk of impingement.

Bone Spurs

Bone growth on the underside of the acromion may reduce the space available for the rotator cuff tendons, contributing to impingement.

Shoulder Injury

Falls, trauma or sudden force applied to the shoulder can lead to inflammation and swelling of the rotator cuff tendons or bursa.

Poor Posture or Shoulder Mechanics

Improper shoulder movement patterns and poor posture can contribute to abnormal stress on the rotator cuff and surrounding tissues.

Preexisting Medical Conditions

Certain conditions, such as rheumatoid arthritis, may contribute to inflammation around the shoulder joint and increase the risk of bursitis.

Symptoms of Shoulder Impingement and Bursitis

Symptoms often develop gradually and may worsen over time if untreated.

Common symptoms include:

• Pain when lifting the arm or reaching overhead
• Shoulder pain that worsens with activity
• Difficulty reaching behind the back
• Weakness in the shoulder or arm
• Reduced range of motion
• Tenderness around the shoulder
• Pain that radiates down the arm
• Difficulty sleeping on the affected shoulder
• Grinding or catching sensation during movement

In some cases, symptoms may begin as mild discomfort during activity but progress to persistent pain even at rest.

When to See a Shoulder Specialist

Consider seeing a shoulder specialist if you experience:

• Persistent shoulder pain lasting more than a few days
• Difficulty raising or reaching with your arm
• Weakness in the shoulder
• Pain that travels down the arm
• A grinding sensation when moving the shoulder
• Pain that interferes with sleep or daily activities

Early evaluation can help identify the underlying cause of shoulder pain and prevent worsening damage to the rotator cuff or surrounding structures.

Diagnosing Shoulder Impingement and Bursitis

Diagnosis typically begins with a detailed medical history and physical exam by an orthopedic specialist. The physical exam allows your provider to evaluate shoulder movement, strength and areas of tenderness.

Imaging tests may also be used to confirm the diagnosis and rule out other shoulder injuries.

Common imaging tests include:

• X-rays to identify bone spurs or structural changes
• MRI to provide detailed images of the rotator cuff tendons, bursa and soft tissues
• Ultrasound to evaluate tendon inflammation or bursitis

These evaluations help determine whether symptoms are caused by impingement, bursitis, rotator cuff injury or another shoulder condition.

Non-Surgical Treatment for Shoulder Impingement and Bursitis

Most cases of shoulder impingement and bursitis can be treated successfully without surgery.

Treatment often focuses on reducing inflammation and limiting activities that aggravate the shoulder.

Common non-surgical treatments include:

Rest and Activity Modification

Avoiding repetitive overhead movements allows inflamed tissues time to heal.

Anti-Inflammatory Medications

Nonsteroidal anti-inflammatory drugs may help reduce pain and swelling.

Physical Therapy

Physical therapy exercises focus on strengthening the rotator cuff and improving shoulder mechanics. This helps reduce pressure within the joint and restore normal movement.

Ice or Heat Therapy

Cold therapy may reduce inflammation and pain, while heat can help loosen tight muscles.

Corticosteroid Injections

In some cases, a subacromial injection may be used to reduce inflammation in the shoulder and relieve pain.

These treatments are often combined to restore shoulder function and prevent recurrence.

Surgical Treatment Options

Surgery is rarely needed to treat bursitis and is typically considered only in cases that do not improve with conservative treatment.

Minimally invasive arthroscopic shoulder surgery may be used to treat persistent impingement or bursitis. During arthroscopic surgery, the surgeon may remove inflamed bursal tissue, bone spurs or other structures contributing to compression.

Procedures may include:

• Subacromial decompression, which increases space in the shoulder by removing bone spurs or reshaping the acromion
• Removal of inflamed bursal tissue
• Repair of associated injuries such as rotator cuff tears

In rare cases of infected bursitis, surgical drainage may be necessary to treat the infection.

Arthroscopic surgery uses small incisions and specialized instruments, which may allow for faster recovery compared with traditional open surgery.

Recovery and Rehabilitation

Recovery depends on the severity of the condition and the type of treatment performed.

Most patients benefit from a structured rehabilitation program focused on:

• Restoring range of motion
• Strengthening shoulder muscles
• Improving joint stability
• Preventing future injury

Many patients return to normal daily activities within several weeks after non-surgical treatment. Surgical recovery may take several months depending on the procedure performed.

Preventing Shoulder Impingement

While not all shoulder injuries can be prevented, several strategies may help reduce the risk of shoulder impingement and bursitis:

• Maintain proper posture
• Warm up and stretch before exercise
• Strengthen shoulder and upper back muscles
• Avoid repetitive overhead motions when possible
• Use proper technique during sports or physical activity

Maintaining shoulder strength and flexibility can help protect the joint from excessive stress.

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