The trapezius muscle (Trapz) is a large muscle consisting of four parts covering the upper back, shoulders and neck. It is used in shrugging the shoulders and with overhead movements.
The Pectoralis Minor muscle is the smallest of the two pectoral (chest) muscles. It works together with Serratus anterior which protracts and rotates the scapula upwards. When the two work together, pure protraction (without rotation) is produced.