Shoulder pain often stems from conditions like impingement syndrome and bursitis. Accurately identifying the cause of shoulder discomfort is important for effective treatment.
Understanding Shoulder Impingement and Bursitis
Shoulder impingement occurs when tissues within the shoulder are compressed or “pinched.” This typically involves the rotator cuff tendons and the bursa in the subacromial space, the area beneath the acromion (the top outer edge of the shoulder blade). The rotator cuff, a group of four muscles, connects the shoulder blade to the upper arm bone, facilitating overhead arm movement and rotation. When these tendons swell, they can become too large for this space, leading to impingement.
Shoulder bursitis involves inflammation of a bursa, a small, fluid-filled sac that cushions bones and soft tissues in joints. In the shoulder, the subacromial bursa cushions the space between the rotator cuff tendons and the acromion. When this bursa becomes irritated, it swells, causing pain and contributing to impingement symptoms.
These two conditions often coexist or can lead to one another. Inflammation of the bursa can narrow the subacromial space, increasing the likelihood of tendon impingement. Similarly, irritated rotator cuff tendons can swell, inflaming the bursa. This creates a cycle where inflammation and swelling in one structure exacerbates problems in the other, leading to persistent shoulder pain.
Individuals experiencing shoulder impingement and bursitis frequently report pain, particularly with overhead activities or when reaching. The pain is often described as a dull ache, sometimes with sharp pain during specific movements, and can radiate from the front of the shoulder down the side of the arm. Night pain, especially when lying on the affected shoulder, is also common and can disrupt sleep. Weakness and a limited range of motion can also occur, making everyday tasks difficult.
Physical Examination Tests for Diagnosis
A healthcare professional relies on a physical examination to assess for shoulder impingement and bursitis, using specific maneuvers to identify pain, weakness, or limitations. These tests help pinpoint the structures involved and guide further diagnostic steps.
The Neer’s Impingement Test evaluates for subacromial impingement, particularly involving the rotator cuff tendons and bursa. During this test, the examiner stabilizes the patient’s shoulder blade with one hand while passively raising the patient’s arm forward and upward, palm down, causing internal rotation. Pain elicited during this motion, especially near the end range of elevation, indicates potential impingement of the supraspinatus tendon or subacromial bursa.
The Hawkins-Kennedy Impingement Test is another common assessment for subacromial impingement. For this test, the patient’s arm is raised to 90 degrees of forward flexion, and the elbow is bent to 90 degrees. The examiner then internally rotates the humerus by rotating the forearm downwards. Pain provoked by this internal rotation indicates a positive test, as it compresses the supraspinatus tendon and subacromial bursa against the coracoacromial ligament and acromion.
The Empty Can Test, also known as the Jobe test, primarily assesses the integrity and strength of the supraspinatus muscle, a key component of the rotator cuff. The patient holds their arm out to the side at a 90-degree angle, with the thumb pointing downward, as if emptying a can. The examiner applies downward resistance, and weakness or pain during this resistance suggests supraspinatus pathology, which can be associated with impingement.
The Painful Arc Test helps identify conditions like impingement syndrome by observing the range of motion where pain occurs. As the patient actively raises their arm out to the side, a painful arc of movement is noted between 60 and 120 degrees of abduction. Pain in this specific range, which then decreases above or below it, is characteristic of subacromial impingement or bursitis.
Imaging and Further Diagnostic Tools
While physical examination tests are foundational in diagnosing shoulder impingement and bursitis, imaging studies play an important role in confirming the diagnosis, evaluating the extent of tissue damage, and excluding other potential causes of shoulder pain.
X-rays are often initial imaging tests. These images are useful for visualizing bony structures and can help rule out conditions such as bone spurs on the acromion, arthritis, or fractures, which might contribute to impingement by narrowing the subacromial space. While X-rays do not show soft tissues like tendons or bursae, they can provide indirect evidence of chronic impingement through changes in bone morphology.
Ultrasound imaging offers a real-time, dynamic view of soft tissues within the shoulder. This modality is effective in visualizing the rotator cuff tendons and the subacromial bursa, allowing for the detection of inflammation, fluid accumulation within the bursa, or even partial tears in the tendons. Ultrasound can also assess tendon movement during arm motion, which can reveal impingement not apparent in static images.
Magnetic Resonance Imaging (MRI) provides highly detailed images of both bony and soft tissues. An MRI can clearly show inflammation of the bursa, rotator cuff tendonitis, and various types of rotator cuff tears, ranging from partial to full-thickness. It can also identify other potential issues such as labral tears or cartilage damage, offering a complete picture of the shoulder’s internal structures and helping differentiate between various causes of pain.
Interpreting Results and Next Steps
A definitive diagnosis of shoulder impingement or bursitis integrates information from several sources to form a comprehensive understanding of the patient’s condition. This involves a thorough review of the individual’s medical history, including the nature and duration of their symptoms, combined with the findings from the physical examination. Insights from imaging studies, such as X-rays, ultrasound, or MRI, further contribute to this diagnostic process by revealing specific structural changes or inflammation.
Once a diagnosis is established, the healthcare provider can recommend a tailored treatment plan. Initially, management often focuses on conservative approaches aimed at reducing pain and inflammation while restoring shoulder function. This can include rest, applying ice to the affected area, and engaging in targeted physical therapy exercises to improve strength, flexibility, and posture. Over-the-counter or prescription anti-inflammatory medications may also be used to manage discomfort.
If conservative measures do not provide sufficient relief, other interventions might be considered. Corticosteroid injections into the subacromial space can help reduce inflammation and pain, offering temporary relief. In some cases, particularly when there are structural abnormalities or significant tears that do not respond to other treatments, surgical intervention may be discussed to widen the subacromial space or repair damaged tissues. The specific course of action is always determined based on the individual’s unique presentation and the severity of their condition.