The serratus anterior muscle is located toward the top and side of your rib cage. This finger-like muscle stabilizes the scapula and assists in elevating your arm. The serratus anterior also helps lift the ribs to assist in respiration. Sometimes called the boxer's muscle, the serratus anterior is heavily involved in stabilizing the arm and shoulder when you throw a punch. Like any muscle, the serratus anterior can become tight and sore. Basic stretches can help alleviate tightness and preserve or improve mobility.
Do the overhead stretch. Stand with one foot in front of the other with both toes pointing forward. Interlock your fingers with your palms facing away from your body. Straighten your arms in front of you and stretch them over your head without arching your back. Hold this position while breathing deeply for 20 to 25 seconds. Switch foot positions and repeat for 20 to 25 additional seconds.
Perform the fascia stretch. Stand straight with your feet close together. Keeping both arms straight, raise them to your sides with your palms facing the ceiling. When your arms are above shoulder-height, hold the position and squeeze your shoulder blades together. Hold this position while breathing steadily for 20 to 25 seconds.
Do a partner-assisted lying serratus stretch. Lie on your side with one arm underneath you and your legs straight. Bend your upper arm and rest your palm on the upper part of your waist so your thumb is pointed toward your pelvis and your fingers are nearly touching your lower back. Have a partner gently and slowly press on your elbow, driving it backward. Once you feel tension in the serratus, have your partner hold your elbow in this position for 20 to 25 seconds. Switch sides and repeat with the other arm.