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: Anatomy
Muscle attached to the tubercle of 1st cervical vertebrae 
Select and explain. 
A. Scalenus anterior, B. Scalenus medium, C. Scalenus minimum, D. Scalenus posterior
B: Scalenus medium
Answer: B: Scalenus medium 
Explanation: None