Shoulder pain is a common complaint, often involving the rotator cuff, a group of four muscles and their tendons stabilizing the shoulder joint. A frequent source of this discomfort is subacromial impingement syndrome (SAPS), where soft tissues become pinched in the narrow space beneath the acromion, the bony roof of the shoulder. Since immediate advanced imaging is not always practical, clinicians rely on specific physical examination maneuvers, such as the Neer and Empty Can tests, to localize the source of pain and guide initial treatment. These tests are designed to reproduce a patient’s symptoms, offering clues about the underlying injury before more costly procedures are considered.
The Neer Impingement Sign
The Neer test is a passive maneuver designed to provoke pain associated with general subacromial impingement syndrome. This condition involves the mechanical compression of structures like the supraspinatus tendon, the long head of the biceps tendon, or the subacromial bursa. It remains a standard initial screening tool for shoulder impingement.
To perform the test, the examiner stabilizes the patient’s shoulder blade (scapula) to prevent compensatory movement. The patient’s arm is placed into full internal rotation, pointing the thumb toward the floor. The arm is then passively lifted forward and upward into maximal forward flexion, forcing the soft tissues against the anterior and inferior surface of the acromion.
A positive Neer sign is indicated by the reproduction of the patient’s familiar pain, typically felt on the front or side of the shoulder, during this forced elevation. This pain indicates that the rotator cuff tendons or the bursa are being squeezed between the head of the upper arm bone (humerus) and the acromial arch. Because the test stresses the entire subacromial space, it is a highly sensitive screening tool for general impingement.
The Neer test has high sensitivity, often reported in the range of 78% to 94%, meaning a negative result makes impingement less likely. However, its specificity is generally lower (54% to 63%). While it is good at ruling out the condition, a positive test alone cannot definitively confirm subacromial impingement because other shoulder issues can also cause pain during this movement.
The Empty Can Test (Jobe’s Test)
The Empty Can Test, also known as Jobe’s Test, assesses the integrity and strength of the supraspinatus muscle and its tendon. Unlike the Neer test, which is a general provocation maneuver, the Empty Can Test is primarily a resisted muscle test. The supraspinatus is responsible for initiating arm abduction, or lifting the arm away from the body.
The procedure requires the patient to position the affected arm in 90 degrees of abduction, 30 degrees forward in the scapular plane. The arm is then maximally internally rotated so the thumb points toward the floor, simulating the action of emptying a can. This position isolates the supraspinatus muscle for testing.
The examiner applies downward resistance to the patient’s arm, and the patient is instructed to hold the position and resist the pressure. A positive finding is not just pain, but observable weakness or a sudden inability to resist the pressure compared to the unaffected side. Weakness during this maneuver is a specific indicator of supraspinatus pathology, suggesting tendinopathy or a partial or full-thickness tear of the tendon.
The Empty Can Test focuses stress on the supraspinatus tendon, making it a valuable tool for pinpointing which rotator cuff structure is injured. Although the test is highly suggestive of a supraspinatus issue, its diagnostic accuracy is variable, with reported sensitivities between 69% and 88% and specificities around 62% to 81%. Interpreting weakness as the primary positive sign, rather than just pain, increases the clinical suspicion of a tendon tear.
Diagnostic Roles and Limitations
The Neer and Empty Can tests serve complementary, yet different, functions in the clinical assessment of shoulder pain. The Neer test is fundamentally a generalized impingement test, designed to reproduce pain by mechanically crowding the subacromial space during passive movement. Its high sensitivity makes it an effective initial screen to determine if impingement is contributing to the patient’s symptoms.
In contrast, the Empty Can Test is a specific assessment of the supraspinatus muscle’s function and structural integrity through resisted effort. If the Neer test is positive, confirming a general impingement issue, the clinician often proceeds to the Empty Can Test to determine if the supraspinatus tendon is involved. This test evaluates the tissue’s ability to generate force under stress.
These tests are most effective when used as a cluster, where multiple positive findings significantly increase diagnostic confidence. No single physical examination test can provide a definitive diagnosis because all maneuvers have inherent limitations in accuracy. For example, the pain elicited by the Neer test could originate from several structures, leading to its lower specificity.
The limitations of both tests mean that a definitive diagnosis of a rotator cuff tear often requires further investigation. Imaging modalities such as magnetic resonance imaging (MRI) or ultrasound provide a clear view of the soft tissues and are the reference standard for confirming tendon tears. The clinical examination tests function as a crucial initial filter, guiding the clinician toward the most likely diagnosis and determining the necessity for advanced imaging.