Pec Minor: A Little Muscle Implicated In Big Problems

Where Is Your Pec Minor?

Pectoralis minor, or pec minor as it is more commonly referred to as, is a muscle that lies in the front lateral area of your chest. Pectoralis minor lies deep to its big brother pec major and as seen in the image below pectoralis minor originates from the third, forth and fifth ribs whilst inserting onto the coracoid process of the scapula (shoulder blade). In relation to your brachial plexus, which is a collection of nerves in your shoulder area that run from your neck to your fingers, you can see from the image below that pec minor is located close to these nerves of the plexus and therefore can have an influence over them. Contracture of the muscle where a short, tight, inflexiable pectoralis minor may in turn produce pain, tingling and numbness in the arm via mechanical impingement on these nerves of the brachial pelxus.

For a fairly small muscle pectoralis minor is considered by many to have a relatively big role.

• The primary actions of pectoralis minor are as a stabiliser of the scapula, assisting  depression, protraction, upward tilt, and downward rotation movements of the shoulder blade.
• Pectoralis minor also acts as an accessory muscle to the inspiration phase of breathing, this comes about when the shoulder blade is fixed contraction of the pec minor muscle can lift the rib cage through its origin off ribs 3-5.

Despite these actions on shoulder movement, scapula stabilisation and breathing, it is typically tightness of pectoralis minor not weakness that is implicated as the culprit in most of the issues involving the muscle and as such stretching and release exercises are commonly prescribed by physiotherapists rather than strengthening exercises.

Pectoralis Minor And Poor Posture

Following spending hours each day, month after month, year after year sitting at your desk with slumped shoulders, your body eventually becomes accustomed to this poor postural behavior. As such muscles including the pec minor muscle tighten, shortening over time making these poor postures progressively harder and harder for the individual to correct. Poor posture contributed to by a tight pectoralis minor muscle can contribute to a number of aches and pains in the neck, shoulder and upper back, as well patterns of scapula dyskinesis (malpositioning and movement of the shoulder blade). Pectoralis minor strength and length is useful in assisting moving and stabilizing the shoulder blade if tight the resulting scapula dyskinesis can contribute to shoulder pain, commonly shoulder impingement, bursitis and rotator cuff disorders as the roof of the shoulder is “pulled down” from a tight pec minor potentially leading to more compression on the bursa and tendons traversing between the joint and the “roof”. For further clarity around the impact of a tight pec minor see the subsequent blog titled “Pectoralis Minor And Poor Posture”.

Disclaimer: Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance on Pec Minor: A Little Muscle Implicated In Big Problems should consult his or her general practitioner, sports medicine specialist, physiotherapist or otherwise appropriately skilled practitioner.