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: Surgery
Thoracic outlet syndrome is primarily diagnosed by: 
Select and explain. 
A. Clinical Evaluation, B. CT scan, C. MRI, D. Angiography
A: Clinical Evaluation
Answer: A: Clinical Evaluation 
Explanation: • TOS refers to compression of subclavian vessels and nerves of the brachial plexus in the region of the thoracic inlet.
• Divided into: Vascular forms (Arterial and /or Venous) and Neurogenic forms
• Compression resulting from TOS is dynamic and best evaluated clinically by mechanical provocative maneuvers
• Symptoms most commonly develop secondary to neural compromise
• Middle-aged women are most commonly affected