what muscle lies beneath the pectoralis and between the ribs
When the raised arms are fixed (as in mountain climbing), it assists the latissimus dorsi and teres major muscles in pulling the trunk up. The pectoralis minor lies, for the most part, beneath the pectoralis major, arising from the middle ribs and inserting into (attaching to) the scapula (shoulder blade). It aids in drawing the shoulder forward and downward (in opposition to the trapezius muscle).