A person is able to abduct his arm, internally rotate it, place the back of hand on the lumbosacral joint, but is not able to lift it from back, What is the Etiology?

The test described in the question is lift off test which is a test for subsacapularis muscle Internal rotation lag sign test The purpose of this test is to assess tears of the subscapularis muscle. 1. The patient is asked to bring the arm behind the back with the palm facing outwards. 2. The arm is held in near maximum internal rotation and with the hand away from the back by approximately 20deg of extension. 3. The patient is asked to hold the position while the examiner suppos the elbow but releases the wrist hold. 4. If the patient is unable to hold the position, the lag sign is positive. Refer Apleys Ohopedic 9th/e 345