The "empty can test" has been described to isolate
The test is considered positive if weakness, pain or both are present during resistance. A positive test result suggests a tear to the supraspinatus tendon or muscle, or neuropathy of the suprascapular nerve.
The empty and full can tests are frequently used for the clinical diagnosis of rotator cuff tears, which elicit weakness or pain secondary to a torn supraspinatus tendon [10, 11].
The full-can position is described as holding the arm at 90° elevation in the scapular plane (30° anterior to the frontal plane) with full external rotation while the empty can position is achieved by holding the arm at 90° elevation in the scapular plane with full internal rotation (Figure 2).
The special tests described in this review evaluate specific tendons of the rotator cuff. The Jobe's test and drop arm test evaluate the supraspintus whereas the lift-off test, passive lift-off, and external rotation lag signs assess the infraspinatus and teres minor.
The two most popular special tests for shoulder impingement are the Neer test and the Hawkins test. In the Neer test, the examiner stabilizes the scapula while passively elevating the shoulder, in effect impinging the humeral head into the acromion.
The "empty can test" has been described to isolate supraspinatus muscle activity from the activity of other rotator cuff muscles. The shoulder is positioned in 90 degrees of abduction, with full internal rotation, and 30 degrees of forward flexion and maintained against resistance.
The drop arm test is used to assess for full thickness rotator cuff tears, particularly of the supraspinatus.
Ultrasound does have the ability to identify rotator cuff tendon tears but with certain limitations. One factor is that it requires special training for the staff, as this is a less commonly performed imaging test. Second, the tendons may not be adequately seen in obese patients or those with a limited range of motion.
The accuracy of the tests was the greatest when muscle weakness was interpreted as indicating a tom supraspinatus tendon in both the full can test (75% accurate) and the empty can test (70%) accurate).
A partial or complete rotator cuff tear makes it difficult to raise and move your arm. You may have shoulder pain and arm weakness. Rotator cuff injuries are common, especially as you get older. Rest, pain relievers and physical therapy can help.
Test for Supraspinatus:
The arm to be tested is moved into 90 degrees of abduction in the plane of the scapula (approximately 30 degrees of forward flexion), full internal rotation with the thumb pointing down as if emptying a beverage can.
Shoulder impingement is a very common cause of shoulder pain, where a tendon (band of tissue) inside your shoulder rubs or catches on nearby tissue and bone as you lift your arm. It affects the rotator cuff tendon, which is the rubbery tissue that connects the muscles around your shoulder joint to the top of your arm.
Jobe's test (or the "empty can" test) assesses supraspinatus function. The patient places a straight arm in about 90 degrees of abduction and 30 degrees of forward flexion, and then internally rotates the shoulder completely. The clinician then attempts to adduct the arm while the patient resists.
Moreover, because the bear-hug test represents the most sensitive test, it can be considered to be the most likely clinical test to alert the surgeon to a possible subscapularis tear. Performing all of the subscapularis tests is useful in predicting the size of the tear.
The Empty Can Test, along with the Full Can Test is a commonly used orthopedic examination test for supraspinatus impingement or integrity of the supraspinatus muscle and tendon. The test is also sometimes called the Empty Beer Can Test. The supraspinatus is one of the four rotator cuff muscles.
The supraspinatus muscle is the only muscle of the rotator cuff that is not a rotator of the humerus. The infraspinatus is a powerful lateral rotator of the humerus. The tendon of this muscle is sometimes separated from the capsule of the glenohumeral joint by a bursa.
MRI provides an accurate anatomic image of the subacromial space, being the current gold standard in the diagnosis of SIS.
Signs and Symptoms of Rotator Cuff Tear
The symptoms of this injury are very similar to that of impingement syndrome, however, a significant amount of weakness comes into play when dealing with a rotator cuff tear.