Review Question - QID 101942

The clinical presentation is consistent with a supraspinatus tear. Weakness to the initiation of abduction would be expected on physical exam in the presence of a complete tear.

The supraspinatus is the most common tendon implicated in a rotator cuff injury, and is the the rotator cuff muscle primarily responsible for the initiation of abduction for the first 15 degrees. On physical exam, the "empty can test" is 90% specific for supraspinatus pathology. This test is performed by having the patient elevate both arms to 90 degrees in the plane of the scapula with the shoulders fully internally rotated, elbows extended, and forearms pronated. This results in the thumbs pointing towards the floor as if the patient is dumping liquid out of a can. In this position the patient resists the examiner's downward force. A positive test is marked by unilateral pain and weakness of the affected arm. Rotator cuff tears can be confirmed with an MRI.

Incorrect Answers:
Answer 1: Adduction in the shoulder is primarily performed by the pectoralis major.
Answer 2: External rotation is primarily performed by infraspinatus and teres minor.
Answer 4: Completion of abduction (above 30 degrees) is primarily preformed by the deltoid.
Answer 5: Internal rotation is primarily performed by subscapularis.