It’s Meet Your Muscle Monday!
I’d like to introduce the Pectoralis Minor. This muscle starts from the coracoid process and splits into three attachments to connect to the 3rd, 4th, and 5th ribs. The coracoid process is a thumb-like part of the shoulder blade on your back that reaches under your collarbone and provides an attachment for muscles on your front.
Most of us know the popular Pectoralis Major, oft admired in mirrors in gyms and bathrooms around the world. The large, fan-like Pec Major is the main ‘pusher’ of the chest, responsible for bringing your arm from outstretched beside you to outstretched in front of you (horizontally adducting the humerus). It’s little brother beneath it, the Pec Minor, is always recruited to help in these jobs, as well as the jobs of the shoulder muscles, but being attached to the shoulder blade and not the upper arm gives it it’s own special function, and it’s own special problems. It’s main jobs are to stabilize the ‘floating’ bone of the shoulder blade, attached to nothing but the muscles it provides a base for. When we flex, thus shorten the pec minor, it pulls and rotates the shoulder blade down. Imagine your shoulder blades as wings and the action of the pec minor as spreading those wings by pulling their corners in.
Aside from being an accessory muscle in breathing (because of it’s attachment at the ribs), the pec minor is responsible for relatively small jobs in movement and stabilization. Despite its small role and stature, this little muscle can cause big problems. It’s unique position attaching ribs in the front to the scapula in the back means that it covers the passage of the brachial plexus (an important bundle of nerves leaving the neck and supplying the arm with sensation and movement) as well as the major axillary (armpit) artery and vein. What this means is that when it becomes chronically shortened or tight from posture or overuse, it compresses these nerves, arteries and veins and creates pain and loss of movement/sensation in seemingly unrelated structures.
Trigger points (tight bundles of muscle fibers) developed in the pec minor will often create pain, tingling or numbness starting in the shoulder and radiating all the way down the side of the arm into the pinky, ring and middle finger. Massage therapy clients describing these symptoms rarely suspect nerve compression and are always somewhat surprised that treating the feelings in their hand and arm starts with deep tissue work up in their chest.
Why is this relevant to the athlete? The chest is a trophy muscle that often gets overworked without proper recovery. This is because we can readily see it and monitor its growth and development. It’s exercises are usually the first we learn and develop comfort with when pursuing a fitness lifestyle. When this muscle is over trained and chronically in a shortened position, one can create an unbalanced physique with the forward-rounded shoulders so often seen in gyms around the bench press area. Appearance aside, the compression of the axillary artery and vein pinches off the supply of nourishment of oxygenated blood to the muscles of the arms and hands. The compression of the nerves of the brachial plexus reduces the transmission of sensory and motor signals too. This means the arms and hands are less able to recognize what’s happening to them and where they are in space as well as being less able to respond quickly and accurately to what the brain is telling them to do. Having responsive and well nourished arms and hands should be of interest to any athlete trying control and take their body to higher levels of performance.
To return a tight Pectoralis Minor to it’s healthy length and open up the space for these important vessels and structures to pass through, I always recommend deep tissue massage. The pec minor is highly responsive to this treatment. At home, you can stretch the pec minor with the very popular ‘doorway stretch’, that is, standing in a doorway with your elbows out in a T position (like you were flexing your biceps) and leaning into the stretch with the edges of the door pushing your elbows back. This is a good stretch for the Pec Major too, so try moving slightly into a Y position to target the pec minor directly. Hold the stretch for at least 90 seconds. Inhale and feel the musculature tighten up. Then exhale and let the breath take all tension with it. Let each exhale gently ease you deeper into the stretch. The key to stretching is consistency and duration. Don’t rush it. Do more than 90 seconds if you wish, but never less. Try to do it every day until you feel the range of motion has increased.
I hope you have enjoyed getting to know the Pectoralis Minor and creating a greater understanding and awareness of what is going on inside your body. Next muscle, next Monday!