Maintaining shoulder health is important for daily activities and overall well-being. When shoulder pain or weakness arises, healthcare professionals often employ specific diagnostic tests to pinpoint the underlying issue. The empty can test is one such common assessment used to evaluate shoulder problems.
Understanding the Supraspinatus and the Test
The supraspinatus muscle is located in the upper back, within the supraspinous fossa of the scapula, or shoulder blade. It is one of four muscles that make up the rotator cuff, a group of muscles and tendons surrounding the shoulder joint. The supraspinatus stabilizes the glenohumeral (shoulder) joint and initiates arm abduction, the movement of lifting the arm away from the body. It performs the first 0-15 degrees of abduction and assists the deltoid muscle in further abduction up to 90 degrees.
The empty can test, also known as the Jobe test, is a clinical assessment specifically designed to evaluate the integrity and strength of the supraspinatus muscle and its tendon. It helps to identify potential weakness, pain, or injury in this muscle, which can be caused by conditions such as tendinopathy, impingement, or tears. The test attempts to isolate the supraspinatus muscle to provide valuable information regarding its condition.
Performing the Empty Can Test
A healthcare professional, such as a doctor or physical therapist, performs the empty can test with the patient typically in a seated or standing position. The patient is asked to abduct both shoulders to 90 degrees. The arms are then brought forward approximately 30 to 45 degrees in the scapular plane, which is angled between the front and side of the body.
Next, the patient internally rotates their arms so that their thumbs point downward, mimicking the action of emptying a can. The examiner then applies downward pressure just above the wrists or elbows, asking the patient to resist this force. Throughout the test, the healthcare professional observes for any pain, weakness, or inability of the patient to maintain the position against resistance.
Interpreting Results and Subsequent Steps
A “positive” empty can test result is indicated by pain in the superior or lateral shoulder, observable weakness when resisting downward pressure, or an inability to hold the arm in the test position. Conversely, a “negative” result implies no pain or weakness during the test. A positive test suggests potential issues with the supraspinatus muscle or tendon, such as tendinopathy, impingement, or even a tear.
The empty can test is part of a broader diagnostic process and is not definitive on its own. Studies show varied reliability and diagnostic accuracy for the test when used in isolation. For a more complete clinical picture, it is combined with other shoulder special tests, patient history, and functional assessments.
Following a positive empty can test, subsequent steps may include further diagnostic imaging to confirm the diagnosis and assess the extent of the injury. Magnetic Resonance Imaging (MRI) or ultrasound are common imaging techniques for this purpose. Treatment options vary based on the diagnosis and severity, beginning with conservative measures such as relative rest from aggravating activities, applying ice to reduce inflammation, and using non-steroidal anti-inflammatory drugs (NSAIDs) for pain management. Physical therapy is recommended, focusing on strengthening the rotator cuff, improving scapular stabilization, and correcting shoulder mechanics. If conservative approaches are insufficient after several months, corticosteroid injections may be considered, or a surgical consultation for procedures like arthroscopic debridement or repair may be necessary.