Protraction is an anatomical term used to describe the action of drawing the shoulder blades anteriorly and slightly apart. This scapular protraction produces a visible pushing forward of the shoulders. While the term protraction can be used to describe a forward-pushing movement of several other body parts, such as the head relative to the neck, it most commonly refers to the specific action at the shoulder girdle.
The opposite of retraction, which involves bringing the shoulder blades backward and together, protraction is made possible by multiple muscle groups in the upper body. Of these, the most significant is the serratus anterior. The serratus anterior is located just below the pectorals and above the abdominals on either side of the ribcage. Originating along the side of the chest from the topmost eight or nine ribs, it wraps around the side of the body and inserts along the medial or inside edge of the shoulder blade. It has a ribbed appearance as its fibers run parallel to the ribs: horizontally and angling slightly upward as they travel away from the midline of the body.
In addition to protracting the scapulae, the serratus anterior aids in scapular stabilization and rotation, helping to turn the shoulder blades upward as it draws them anteriorly. This muscle is highly pronounced in boxers, who use it to protract the scapulae as they throw a punch. In this case, protraction is also a useful tool for defense: inwardly rounding the shoulders and pulling them forward creates a smaller surface area of the torso for an opponent the land a punch, and therefore less area to protect with the arms.
Another muscle used in shoulder blade protraction is the pectoralis minor. Much smaller than its neighbor in the chest, the pectoralis major, the pectoralis minor is found beneath it. Instead of its fibers running horizontally, however, the pectoralis minor runs perpendicularly to the pectoralis major, with its fibers vertically spanning the upper ribcage. Attaching via a tendon to the top inside portion of the shoulder blade, the pectoralis minor is primarily responsible for depressing the shoulder, or pulling it downward, but it also participates in protraction by tilting the inside edge of the scapula backward as the serratus draws the scapula forward.
In many individuals, particularly those who sit in front of a computer all day, the muscles involved in protraction are tight and overdeveloped. This imbalance can be corrected by strengthening the muscles involved in retraction, those found between the shoulder blades in the upper back like the rhomboids, as well as stretching the protractors. Doing so will help pull the shoulders back where they belong into neutral postural alignment.