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
Axillary sheath is an extension of- 
Select and explain. 
A. Pretracheal fascia, B. Prevertebral layer of deep cervical fascia, C. Investing layer of deep cervical fascia, D. None
B: Prevertebral layer of deep cervical fascia
Answer: B: Prevertebral layer of deep cervical fascia 
Explanation: Ans. is 'b' i.e., Prevertebral layer of deep cervical fascia 'Axillary sheath and fascia around trunk of brachial plexus are derived from prevertebral fascia (prevertebral layer of deep cervical fascia).'