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
Triangle of auscultation is impoant in clinical practise. The boundary of which is not formed by? 
Select and explain. 
A. Serratus anterior, B. Scapula, C. Trapezius, D. Latissimus dorsi
A: Serratus anterior
Answer: A: Serratus anterior 
Explanation: The triangle of auscultation is a small triangular interval bounded,Superiorly by the trapezius muscleInferiorly by the latissimus dorsiLaterally by the medial border of the scapulaThis is the only pa of the back which is not covered with muscles. Respiratory sounds are better heard with a stethoscope here than that heard elsewhere in the back.