Shoulder pain is a common complaint requiring a detailed physical examination to determine the source of discomfort. Clinicians use specific physical maneuvers, known as special tests, to help differentiate between causes of shoulder problems, such as a tendon tear versus inflammation. These tests offer clues about the integrity of the rotator cuff muscles and the presence of compression within the joint space. Two widely used maneuvers for this purpose are the Neer Test and the Empty Can Test, each focusing on a distinct mechanism of injury.
The Neer Test: Assessing Impingement
The Neer Test is a clinical procedure intended to identify subacromial impingement syndrome, which occurs when tendons or bursa are pinched between the bones of the shoulder joint during movement. The maneuver involves the examiner passively lifting the patient’s arm forward into full elevation while simultaneously internally rotating the arm (thumb down). The examiner often stabilizes the patient’s shoulder blade during this motion to isolate the movement at the shoulder joint.
This passive motion forcefully drives the greater tuberosity of the humerus against the coracoacromial arch, a bony structure at the top of the shoulder. Internal rotation further narrows the space beneath this arch, maximizing the compression of soft tissues. A positive result is the reproduction of the patient’s familiar shoulder pain, typically near the end range of the motion.
The pain suggests that the rotator cuff tendons or bursa are being compressed against the overlying bone. While the test is highly sensitive, meaning a negative result often rules out impingement, a positive result alone does not identify the specific pinched tissue.
The Empty Can Test: Evaluating Supraspinatus Integrity
The Empty Can Test, also known as the Jobe test, is designed to assess the function and structural integrity of the supraspinatus muscle and tendon. The supraspinatus is one of the four rotator cuff muscles and initiates arm abduction (lifting the arm away from the body). The test is performed by having the patient raise their arm to 90 degrees of abduction in the scapular plane (approximately 30 degrees forward from the side).
The patient then rotates the arm internally so the thumb points toward the floor, mimicking the action of emptying a can. This position places maximum stress on the supraspinatus tendon as it attempts to maintain the arm’s position.
The examiner applies a downward force to the forearm, and the patient is instructed to resist this pressure. A positive result is indicated by either significant pain or noticeable weakness when the patient resists the downward force. Weakness during this maneuver indicates a tear or significant injury to the supraspinatus tendon or muscle. The test isolates the supraspinatus, making it a targeted assessment for specific rotator cuff pathology.
Key Differences in Diagnostic Focus
The fundamental difference between the Neer Test and the Empty Can Test lies in their primary diagnostic targets and the mechanism of pain they attempt to reproduce. The Neer Test focuses on compression and impingement, checking for pain caused by the mechanical pinching of soft tissues in the subacromial space during movement. It is a general test for subacromial pathology, and a positive finding points toward an inflammatory condition like bursitis or tendonitis.
In contrast, the Empty Can Test is a test of strength and integrity, specifically challenging the supraspinatus muscle-tendon unit against resistance. While pain can occur due to inflammation, a distinct weakness during the maneuver is the key finding that suggests a structural defect, such as a partial or full-thickness tendon tear. The Empty Can Test is muscle-specific, while the Neer Test assesses the subacromial space.
Because neither test is perfectly accurate alone, clinicians often use both, along with other specialized maneuvers, to achieve a comprehensive understanding of the shoulder injury. A positive Neer Test combined with a painful, weak Empty Can Test suggests that underlying impingement may have progressed to cause structural damage to the supraspinatus tendon. The combination of results helps guide decisions about whether the problem is primarily inflammation requiring rest, or a structural tear that might require surgical consideration.