Pectoralis Major: Pain Pattern and Treatment
The pectoralis major spans the chest from the collarbone, sternum, and ribs to the upper arm. Its documented pattern is pain across the chest and the front of the shoulder, running down the inner arm along the ulnar side of the forearm, at times into the fourth and fifth fingers.
Attachments and action
Origin: The medial clavicle, the sternum, and the cartilage of the upper six ribs.
Insertion: The lateral lip of the bicipital groove of the humerus.
Action: Adduction and internal rotation of the arm, with the clavicular head assisting flexion and the sternal head extension from a flexed position.
Where the pain is felt: Across the chest and the front of the shoulder, down the inner arm along the ulnar forearm, at times into the fourth and fifth fingers. On the left side this distribution overlaps the classic cardiac pattern.
Common causes: Bench pressing and push‑up loads, rounded‑shoulder posture, carrying heavy bags across the chest, prolonged bracing of the arms.
Patients say: “A tightness across my chest and down my arm.” Chest wall soreness after pressing workouts. An ache in the front of the shoulder reaching across the body.
When to get evaluated: New chest pain, especially left‑sided with exertion, pressure, shortness of breath, nausea, or sweating, is treated as cardiac until proven otherwise: emergency evaluation comes before any myofascial explanation.
How this muscle is examined and treated
Once cardiac causes are excluded, examination maps the chest wall by muscle region: clavicular, sternal, and costal fibers each carry distinct points, tested with resisted adduction across the body. Needling over the chest wall is shallow and angle‑controlled along the muscle. Assessment and treatment happen in the same visit.
Related conditions
Chronic Pain PatternsShoulder DysfunctionSports & Performance Injuries
This page is educational. It describes muscle referral patterns commonly associated with pain; it does not diagnose your condition. Individual patterns vary. For evaluation of your specific pain, see a licensed clinician. Seek immediate medical care for emergencies. Eugene Baek, L.Ac. · New Jersey License 25MZ00080600