This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Extremity, Subject name: Anatomy
[{'content': 'Fascia around the nerve bundles of brachial plexus is derived from- \nSelect and explain. \nA. Deep cervical fascia, B. Pretracheal fascia, C. Prelaryngeal fascia, D. None', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Deep cervical fascia * The axillary sheath is a fibrous sheath that encloses the first portion of the axillary artery, together with the brachial plexus. The axillary vein lies entirely outside the sheath It is an extension of the prevertebral fascia of the deep cervical fascia.* A brachial plexus nerve block can be achieved by injecting anaesthetic into this area.", 'role': 'assistant'}]