what is the largest muscle in the neck called
The pectoralis minor is located underneath the pectoralis major. This thin triangle-shaped muscle runs up and down along the upper ribs. The major muscles in the upper torso include: 1  Trapezius: This muscle extends across the neck, shoulder, and back. 2  It allows for movement of the shoulders and shoulder blades.3  Rhomboid major: Attached to the shoulder blade, this muscle is one of many that aids shoulder movement.his thin triangle-shaped muscle runs up and down along the upper ribs. The major muscles in the upper torso include: 1  Trapezius: This muscle extends across the neck, shoulder, and back. 2  It allows for movement of the shoulders and shoulder blades.