This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
Boundary of triangle of auscultation 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: Triangle of auscultation is a small triangular interval on the back of thorax bounded by: medially - lateral border of trapezoid laterally -medial border of scapula inferiorly - upper border of latissimus dorsi. The floor- 6th & 7th rib, 6th intercoastal space , rhomboid major. B D Chaurasia 7th edition Page no : 67 Figure 5.6,page no: 63 - Textbook of anatomy- upper limb & thorax - vishram singh