This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
[{'content': 'Lift off test is done to assess the function of - \nSelect and explain. \nA. Supraspinatus, B. Infraspinatus, C. Teres minor, D. Subscapularis', 'role': 'user'}, {'content': "Answer: D \nExplanation: Lift Off Test (Gerber's test) \n\nLift off test is done to assess the strength of subscapularis muscle and detect a rupture of the subscapularis tendon.\nSubscapularis functions primarily as an internal rotator of the shoulder\nThe test is performed with the arm extended and internally rotated such that the dorsum of the hand rests against the lower back.\nThe subscapularis is maximally active in this position.\nThe patient is then instructed to lift his/her hand off the back (Lift - off) (Attempting further internal rotation)\nIf the patient is able to lift the dorsum of the had off the back the subscapularis tendon is intact and the test is considered negative.\nIf the patient is not able to lift the dorsum of the hand off the back the subscapularis tendon is torn and the test is considered positive.\nThe lift-off test\nis a sensitive and specific test for subscapularis function and this has been validated by electromyography studies.", 'role': 'assistant'}]