The Pectoralis minor is a muscle that does not live up to its name! Its effects on our posture and functioning can be more than trivial! Photo A
The Pectoralis minor is a muscle that does not live up to its name! Its effects on our posture and functioning can be more than trivial! The muscle is termed “minor” in relation to its big brother Pectoralis major. It inserts on the coracoid process at the front of the scapula, and runs down to attach to ribs 3 to 5 Its major action is to depress the shoulder and to draw the scapula anterior and inferior (protraction). In the photograph above (A) you can see Pec minor in blue being stretched somewhat in our Innovations in Pilates reformer rotation exercise. In this exercise, we encourage retraction of the scapula using the rhomboid and mid trapezius muscles also, so that the Pec minor can assist with inspiration by lifting the ribcage. Posturally the Pec minor can be problematic because of its effect on the scapula. As a tight Pec minor rolls the shoulder girdle forward on the ribcage, the clavicles drop onto the first thoracic rib causing brachial plexus compression. Symptoms like an electric shock or a burning sensation shooting down your arm, or numbness or weakness in the arm can result.
A tight Pec minor can also effect the biomechanical function of the entire shoulder girdle. Impingement syndrome is a malady that can occur in combination with Pec minor drawing the scapula forward off the rib cage. In Pilates there are many exercises that require quite a deal of flexibility in Pec minor to be performed correctly and safely. Take a look at the Matwork photos below that require opening of the chest for correct performance-the Double Leg Kick (B), Rocking (C) and the Leg Pull Front (D). On the reformer, the Stomach Massage (hands behind version), and Chest Expansion are just two examples.
Photo B
Photo C
Photo D
To assess the length of Pec minor, try this simple test. Lie on a mat or table as pictured, (E) and check the position of the front of the shoulders. Notice the left shoulder in the photo below? It is lifted and the shoulder blade doesn’t drop comfortably onto the mat. A lift of 5 cm is regarded as tight in most texts.