Boundary of triangle of auscultation is not formed by

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