This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb : Miscellaneous, Subject name: Anatomy
[{'content': 'Anastomosis around the shoulder is between branches of: \nSelect and explain. \nA. 1st pa of subclan and 1st pa of axillary aery, B. 1st pa of subclan and 3rd pa of axillary aery, C. 3rd pa of subclan and 2nd pa of axillary aery, D. 3rd pa of subclan and 3rd pa of axillary aery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - Shoulder anastomosis occurs between branches of 1st pa of subclan aery and 3rd pa of axillary aery. - Two sites of scapular anastomosis: 1. Around the body of scapula: (a) suprascapular aery (branch of the thyrocervical trunk from the first pa of the subclan aery) (b) circumflex scapular aery (branch of the subscapular aery from the third pa of the axillary aery) (c) deep branch of the transverse cervical aery (branch of the thyrocervical trunk) 2. Over the acromion process: (a) acromial branch of the thoraco-acromial aery (b) acromial branch of the suprascapular aery (c) acromial branch of the posterior circumflex humeral aery.', 'role': 'assistant'}]