This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb bones and muscles (proximal region) & Scapular movements, Subject name: Anatomy
[{'content': 'Retraction of scapula at sternoclavicular joint is done by: \nSelect and explain. \nA. Serratus anterior, B. Trapezius, C. Subscapularis, D. Supraspinatus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Retraction means moving backward of scapula at sternoclavicular joint. It is done by the following muscles: Trapezius Rhomboid major Rhomboid minor. Subscapularis helps in medial rotation of humerus. Serratus anterior helps in protraction of scapula. Supraspinatus helps in adduction.', 'role': 'assistant'}]