Muscles: Actions, Origins & Insertions Practice Test

Adduction (retraction) of the scapula is produced by muscles that pull the medial edge of the scapula toward the spine. The rhomboid group does this and specifically attaches along the vertebral (medial) border of the scapula. The rhomboid major inserts on the lower portion of that border and pulls the scapula medially, helping to retract it and downwardly rotate it for stability. The other options don’t fit this pattern: serratus anterior pulls the scapula forward and attaches to the anterior surface of the medial border; trapezius retracts the scapula but its insertion is on the spine of the scapula and the acromion, not the vertebral border; pectoralis minor attaches to the coracoid and protracts the scapula. So the muscle that both adducts the scapula and inserts on the vertebral border is the rhomboid major.