Final answer:
The pectoralis major is not a part of the force-couple for the upward rotation of the scapula, this role is filled by the trapezius and serratus anterior.
Step-by-step explanation:
The muscle that is not part of the force-couple that produces upward rotation of the scapula is the pectoralis major. The force-couple for the upward rotation of the scapula includes the trapezius and the serratus anterior. The rhomboids are involved in moving the scapula medially. The pectoralis major, however, is primarily responsible for moving the humerus as it is attached to the anterior thorax, not the scapula, and hence it is not involved in the rotation of the scapula in the way that the other muscles mentioned are.