Which muscles are involved in the retraction of the scapula?

The retraction of the scapula primarily involves the rhomboids and the middle and lower fibers of the trapezius muscles. These muscle groups work together to pull the scapula towards the spine. The rhomboids, which include the rhomboid major and minor, are specifically positioned to facilitate this movement by drawing the scapulae closer to each other. The trapezius muscle, particularly its middle and lower fibers, also plays a critical role by stabilizing and retracting the scapula, helping to maintain proper posture and shoulder alignment.

While the serratus anterior does play a significant role in the protraction and upward rotation of the scapula, it is not directly involved in retraction. Additionally, the levator scapulae primarily functions to elevate the scapula rather than retract it. Therefore, the correct answer highlights the specific muscles that are directly responsible for the retraction of the scapula.