Special Tests for the Supraspinatus
(1) Full Can / Empty Can Test:
This test involves a contraction of the supraspinatus muscle-tendon unit to try and hold up the arm in a selected position. At the same time one has to oppose a downward pressure that is placed on the arm.
This test is positive for a supraspinatus tendinopathy if weakness (arm drops) and/or pain occurs whilst performing the action. It is a highly specific test (cannot detect the exact location or type of tendinopathy) however it is sensitive (detects an abnormality of the tendon).
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Traditional 'Empty Can' Test position
The positioning of the arm is important to get right.
It involves ‘forward flexion’ of the arm to 90o, held at an angle 45o to the body (“scaption”)
with internal rotation – Empty can
or external rotation - Full can.
This test can be repeated using a retracted scapula (squeeze shoulder blades together) and if strength is greater, the rotator cuff may not be injured. The weakness is due to scapula movement and control errors (Bruckner and Kahn, 2006). It can therefore be used either include or exclude supraspinatus tendinopathy as a possible diagnosis.
(2) Neer Test:
This is an impingement test.
If there is a tendinopathy present, the space (subacromial) between the top of the shoulder blade and humerus (long bone of arm) may be decreased. This means that there is not enough space for the rotator cuff muscle group to function optimally. When you lift the arm up, it causes abnormal blockages and pressures on the internal structures, resulting in pain.
It involves facing the palm of the hand outwards away from the body (internal rotation of the glenohumeral joint) and lifting the arm up as far as possible towards the ear. The physician is looking for any signs of pain or reproduction of symptoms.
(3) Other tests that may implicate supraspinatus tendinopathy for diagnosis:
(a) Painful Arc with abduction (70o-120o)
(b) Drop Arm Test
This test indicates if a rotator cuff tear is present however it is not specific to the supraspinatus.
The physiotherapist supports the weight of the patients arm out in an abducted position and then releases it slowly. If the rotator cuff is injured, weakness will result and the patient will not be able to hold the arm up by themselves. If the arm drops this is a positive test sign.
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