The Pectoralis Major muscle adducts and medially rotates humerus. It has two portions. The Clavicular portion: flexes and medially rotates shoulder joint, and horizontally adducts humerus toward opposite shoulder. The Sternocostal portion:obliquely adducts humerus toward opposite Hip. Pectoralis major is one of the main climbing muscles, pulling the body up to the fixed arm.Trigger points in pectoralis major are fairly common but variations in the pain maps can extensive. In terms of referred pain: Trigger points in the Clavicular portion of the pectoralis major tend to radiate to the anterior deltoid and long head of Biceps Brachii area. Trigger points in the Sternal portion of the Pectoralis major tend to present as “acute” pain in the anterior chest wall in a 10–20 cm patch of diffuse pain around medial border of upper extremity. Patients may also report strong pain below medial epicondyle in a 5 cm patch, diffuse pain into 4th and 5th digits. Trigger points in the costal portion of Pectoralis major tend to radiate into the 5th and 6th ribs – this can even lead to severe cardiac referral (even at night). Intense breast pain (10–15 cm patch). In some people there are also some diffuse radiations into axillary tail, and into the axilla.
Interestingly trigger points may manifest in the pectoralis major muscle after a myocardial infarction; the implications are that trigger points may also be subject to viscero-somatic referral. It is worth checking for trigger points in the pectoralis major muscle in patients who have been in a sling for shoulder problems and also in patients with respiratory issues such as thoracic outlet or hyperventilation syndrome.
How do you treat trigger these trigger points? We’d be delighted if you want to share your own best practice.