Massage therapy · Kitchener–WaterlooPectoralis Minor Syndrome
Neck & Shoulder
What It Is
Pectoralis minor syndrome is numbness, pain, weakness or tingling in the arm and hand caused by pressure on the nerves (and sometimes the blood vessels) that supply the arm, where they pass underneath the pectoralis minor muscle. The pectoralis minor is a small muscle in the upper chest. It lies just below the collarbone, underneath the larger pectoralis major muscle (Sanders and Annest, 2017).
In the closely related condition thoracic outlet syndrome, pressure on the nerves accounts for over 90 percent of cases, with only a small number involving a vein or artery (Jones et al., 2019).
Many people with the condition have had an injury, such as a car accident (including whiplash injuries) or a fall. Repetitive stress is another common cause, for example working on assembly lines or keyboards, or sports such as swimming, baseball pitching, volleyball and weightlifting. In some people, the condition begins without any obvious cause (Sanders and Annest, 2017; Jones et al., 2019).
Poor posture and being overweight can make symptoms worse (AAOS, n.d.).
Pectoralis Minor Syndrome Anatomy
The nerves to the arm (the brachial plexus) travel together with the main artery and vein of the arm in a bundle. This bundle passes from the neck, between two neck muscles (the scalene muscles), under the collarbone, and then below the collarbone underneath the pectoralis minor muscle, where the vessels are called the axillary artery and vein (Sanders and Annest, 2017). The pectoralis minor attaches to a bony point on the shoulder blade called the coracoid process (Sanders and Annest, 2017).
In pectoralis minor syndrome, the bundle is squeezed in the space under the pectoralis minor, below the collarbone. This is different from thoracic outlet syndrome, where the squeezing happens higher up, above the collarbone in the area of the scalene muscles, although some people have both (Sanders and Annest, 2017; Jones et al., 2019).
Not a diagnosis — for more information, contact me or another trusted healthcare provider.
Treatment
Self-Care & Treatment
How to Treat Pectoralis Minor Syndrome
I can help by stretching and lengthening the pectoralis minor and the surrounding chest muscles, working on your posture, and giving you exercises to strengthen the muscles around the shoulder, which helps to support the collarbone (AAOS, n.d.). See the My Approach tab for how I work.
1. Therapy
Stretching the pectoralis minor muscle is the most important treatment for this condition, and stopping the repetitive activity that brought on the symptoms is part of treatment (Sanders and Annest, 2017). Physiotherapy with stretching and strengthening exercises is the usual first treatment (NHS, 2023). Postural re-training is key, so looking at your work set-up and office ergonomics is important. If therapy does not help, your doctor can discuss other options with you.
Treatments you may want to discuss with your family doctor or nurse practitioner
Options outside my scope
Muscle block injection: a specialist may inject a short-acting local anaesthetic into the pectoralis minor muscle to help confirm the diagnosis (Sanders and Annest, 2017).
Botulinum toxin injection: this has been tried to relax the muscle, but a randomised trial found no significant benefit (Jones et al., 2019).
Surgery: an operation called a pectoralis minor tenotomy, which releases the pectoralis minor tendon, may be offered if stretching and therapy have not helped (Sanders and Annest, 2017). Operations to remove the first rib or an extra rib (cervical rib) are used for thoracic outlet syndrome rather than pectoralis minor syndrome (Jones et al., 2019; NHS, 2023).
Hands-on work and stretching for the chest, neck and shoulder muscles
Exercises to strengthen the muscles around your shoulder blade
Advice on posture, breathing and your work set-up
Tips
If you are overweight, you might want to try losing a few pounds, as excess weight can aggravate this condition (AAOS, n.d.).
Try to maintain good posture throughout the day (AAOS, n.d.).
If you have weak shoulder muscles and drooping shoulders, strengthening exercises can help support the collarbone (AAOS, n.d.).
Certain occupations, sports, postural habits and repetitive activities can all contribute to this syndrome (Sanders and Annest, 2017; AAOS, n.d.).
Treatment
My Approach
Pectoralis minor syndrome is a squeeze on the nerves, and sometimes the blood vessels, heading to your arm as they pass under the small chest muscle below your collarbone. My aim is to give them more room: ease the tight muscles, change the postures that close the space, and build the strength to keep it open.
Which path we take depends on your symptoms
If you have pain, tingling or numbness but your strength is normal and things aren't getting worse, I can treat you directly.
If you have weakness, numbness or other nerve signs that are getting worse, or swelling or colour changes in the arm, see your family doctor or nurse practitioner first. Once you've been assessed, I can support your medical team's plan. After surgery, I need your surgeon's okay before any hands-on treatment.
I start by assessing your posture, breathing and shoulder movement, and checking the sensation, reflexes and strength in your arm and hand, which I recheck as we go.
Hands-On Treatment
Massage, myofascial and trigger point work for the chest, the side of the neck, the upper back and the shoulder blade muscles
Gentle release and stretching of the pectoralis minor, keeping pressure light under the collarbone
Gentle nerve glides, and mobilisation of the shoulder blade, collarbone and upper ribs, with no quick or forceful movements
Chest wall work only with your informed consent and a written consent form; work through the armpit needs your informed consent
Exercise and Daily Habits
Stretches for the chest muscles and strengthening for the muscles around your shoulder blade, with a home programme between visits
Breathing low into your belly rather than high into your upper chest
Looking at your work set-up, breaking up repetitive or overhead work, and adjusting your lifting or training where needed
If your arm becomes swollen, red, warm or painful, or you have sudden breathlessness or chest pain, get urgent help (see When to get urgent help).
What to Expect
Typical Course
Typical course: Early on, most people come once or twice a week, then weekly, with a reassessment at about 4 to 6 weeks, then less often as your home programme takes over. In milder cases, expect some improvement by about three months. After medical treatment or surgery, recovery usually takes longer and follows your medical team's plan.
What I Focus On
Assessment
Chest & Neck Release
Shoulder Blade Strength
Breathing & Posture
Daily Habits
Please read
When to See a Doctor First
When to get urgent help
Get urgent medical attention or call 911 for an ambulance if you have throbbing or cramping pain, swelling, redness and warmth in one arm, as these could be signs of a blood clot (NHS, 2023).
Call 911 or go to the emergency room at your nearest hospital if you have sudden breathlessness, sharp chest pain (which may be worse when you breathe in), or a cough or coughing up blood (NHS, 2023).
Sources
References
Sanders, R.J. and Annest, S.J. (2017) 'Pectoralis minor syndrome: subclavicular brachial plexus compression', Diagnostics, 7(3), p. 46. doi: 10.3390/diagnostics7030046
Jones, M.R., Prabhakar, A., Viswanath, O. et al. (2019) 'Thoracic outlet syndrome: a comprehensive review of pathophysiology, diagnosis, and treatment', Pain and Therapy, 8(1), pp. 5–18. doi: 10.1007/s40122-019-0124-2