The rhomboid major is a muscle located in the upper back, specifically between the shoulder blades. It originates from the spinous processes of the upper thoracic vertebrae and inserts into the medial border of the scapula. This muscle plays a crucial role in stabilizing the scapula and assisting in its retraction, which helps pull the shoulder blades together. Functionally, the rhomboid major works alongside other muscles, such as the rhomboid minor and the trapezius, to support shoulder movements. Strengthening this muscle can improve posture and enhance athletic performance, making it important for activities that involve pulling or lifting.