Empty can test

The Empty Can Test, also known as Jobe’s Test or the Supraspinatus Test, is used to assess the function of the supraspinatus muscle and its tendon. The supraspinatus is part of the rotator cuff, and injuries may include tendinitis, partial tears, full ruptures, or impingement. The test can also indicate suprascapular nerve neuropathy¹.

The goal is to reproduce pain or detect weakness under resistance, which may suggest pathological changes in the tendon or muscle itself

Clinically Relevant Anatomy

The supraspinatus is one of four rotator cuff muscles, located in the supraspinous fossa and passing under the acromion to insert on the greater tubercle of the humerus. It is crucial for the first 15° of abduction and works closely with the rest of the cuff and scapular stabilizers.

It is innervated by the suprascapular nerve (C5–C6), and its tendon is particularly prone to compression in the subacromial space during repetitive use or scapular dysfunction¹.

Test Procedure

1. The patient stands or sits upright.

2. The arm is abducted to 90° in the scapular plane (30° anterior to the frontal plane).

3. The shoulder is internally rotated so the thumb points downward (“emptying a can”).

4. The examiner applies steady downward pressure on the forearm or wrist.

5. The test is repeated bilaterally for comparison.

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Interpretation of Findings

• Pain only: Suggests supraspinatus tendinopathy or irritation.

• Weakness only: Indicates possible partial/full rupture or suprascapular nerve neuropathy.

• Pain + weakness: Increases likelihood of clinically significant pathology.

• Negative test: Reduces suspicion but does not rule out early or mild injury.

Alternative Test

The Full Can Test uses the same scapular plane abduction, but with the thumb pointing upward. This reduces subacromial compression and more selectively activates the supraspinatus, especially useful when impingement dominates¹.

Clinical Accuracy

EMG studies show the Empty Can Test activates the supraspinatus up to 90% of maximal voluntary contraction (MVC). However, significant activation also occurs in:

• Infraspinatus

• Subscapularis

• All deltoid portions

• Upper, middle, and lower trapezius

• Serratus anterior³

This makes it difficult to isolate the supraspinatus as the sole contributor to a positive result.

Diagnostic Parameters

Finding	Sensitivity	Specificity	+LR	–LR
Pain	63%	55%	1.40	0.67
Muscle weakness	77%	68%	2.41	0.34
Pain or weakness	89%	50%	1.78	0.22

The test shows higher sensitivity than specificity, making it more useful for ruling out rotator cuff injury than confirming it.

Advantages

• Simple to perform

• Quick in clinical practice

• Requires no equipment

• Well-suited for use in a test battery

Limitations

• Low specificity

• Significant co-activation of other muscles

• Risk of false positives with impingement or scapular dysfunction

Clinical Recommendation

The Empty Can Test should not be used in isolation. It is most valuable as part of a rotator cuff and impingement test battery. Combining it with functional assessments, pain mapping, and imaging where necessary increases diagnostic accuracy.

Sources:

1. Magee DJ. Shoulder. I: Orthopedic Physical Assessment. 7. utg. Philadelphia: Elsevier; 2022.

2. Clinical Physio. Empty Can Test for Shoulder | Clinical Physio Premium. Tilgjengelig fra: https://www.youtube.com/watch?v=mC_5Lmy7iAo&ab_channel=ClinicalPhysio (sist åpnet 05.07.2025)

3. Boettcher CE, Ginn KA, Cathers I. The ‘empty can’ and ‘full can’ tests do not selectively activate supraspinatus. Journal of Science and Medicine in Sport. 2008;12(4):435–439. (sist åpnet 05.07.2025)