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Pectoralis major
The fan-shaped chest muscle that pulls the arm across the body and drives every pushing movement.
Latin name: Musculus pectoralis major. In plain English, the big chest muscle. It is filed here under chest and back.
Reference information, not a diagnosis. Where a symptom is described below, it is there so you can describe your own more precisely to a clinician — not so you can name what you have.
Where it is
Pectoralis major is a broad fan covering the front of the chest, arising along a wide line from the collarbone, down the breastbone, and across the upper rib cartilages. All of that width converges into a surprisingly narrow tendon that attaches to the front of the upper arm bone, just to the outside of the groove where the biceps tendon runs. The fibres twist as they converge, so the ones that started highest end up lowest on the humerus.
The muscle has two functional heads with different lines of pull. The clavicular head runs downward and outward and lifts the arm forward; the sternocostal head runs upward and outward and pulls the arm down and in. This is why an incline press feels like a different exercise from a dip, even though both are pressing.
| Feature | Detail |
|---|---|
| Origin | Clavicular head from the medial half of the clavicle; sternocostal head from the sternum and the costal cartilages of ribs one to six |
| Insertion | Lateral lip of the intertubercular groove of the humerus |
| Nerve | Lateral and medial pectoral nerves (C5-T1) |
| Main actions | Adduction and internal rotation of the arm; the clavicular head flexes the shoulder, the sternal head extends it from a flexed position |
What it does
Its defining action is adduction: bringing the arm toward and across the midline. Everything else follows from that. Pushing a door, throwing, a bench press, a push-up and a boxing punch all combine adduction with some internal rotation, which is exactly what the muscle does best. Climbing and pulling yourself up onto something loads the sternal head hard as the arm comes down past the body.
It is also a respiratory accessory muscle. With the arms fixed — hands braced on the knees or a table — the muscle can pull the rib cage upward instead of pulling the arm, which is why people who are short of breath instinctively lean forward and brace their arms.
Exercises that load it
| Exercise | Category | Muscles the exercise library lists |
|---|---|---|
| Bench press | Strength | Chest, triceps, front shoulder |
| Push-ups | Strength | Chest, triceps, front shoulder, core |
| Dips | Strength | Triceps, chest, front shoulder |
| Swimming, freestyle | Cardio | Whole body, heart, lungs |
Pressing movements load it through its adduction range; the further the arm travels across the body, the more the chest does relative to the shoulders and triceps. Dips load the sternal head in a deep, lengthened position, which is also the position where the tendon is most vulnerable, so it is worth earning depth gradually. Push-ups scale well with hand position and body angle for people training without equipment.
How it is lengthened
A doorway stretch: forearm on the frame at about shoulder height, then step through and turn away. Doing it at three heights — low, level, high — lengthens the different fibre directions. It is the classic answer to a rounded desk posture, though shoulder position depends at least as much on what the upper back and shoulder blades are doing as on chest muscle length.
When it goes wrong
| Problem | What it typically feels like | Usual setting |
|---|---|---|
| Pectoralis major tear | A sudden tearing sensation at the front of the shoulder or armpit with bruising and a change in the muscle contour | Heavy bench pressing, especially at the bottom of the lift where the muscle is lengthened under load |
| Chest wall muscle strain | A local ache that is sore to press on and hurts on deep breaths or twisting | A sudden pushing effort, coughing, or unaccustomed volume |
| Costochondritis | Sharp, reproducible pain at the joints where the rib cartilage meets the breastbone, tender to touch | Often follows a viral illness, a lot of coughing, or unaccustomed upper-body loading |
Chest pain is the one symptom on this site that should never be reasoned about at home. Pressure, tightness or a heavy feeling in the chest, especially with breathlessness, sweating, nausea, or pain spreading to the arm, jaw or back, means emergency help now. Muscle pain is reproducible by pressing on the spot; cardiac pain generally is not, but never rely on that alone.
Nothing on this page is a treatment plan. If a problem is limiting what you do, is not improving, or is getting worse, the right next step is an assessment by a doctor or a physiotherapist who can examine you.
Sources: descriptive anatomy from Gray's Anatomy of the Human Body, 20th US edition (1918), which is in the public domain; Latin names follow Terminologia Anatomica, published by the Federative International Programme for Anatomical Terminology. Nerve root levels are the conventional ranges taught from those sources and vary between individuals and between textbooks. Exercise cross-links use the TempoLife exercise library. Checked 2026-09-06.
Frequently asked questions
What is the difference between pectoralis major and minor?
Major is the large superficial fan that moves the arm. Minor is a small muscle underneath, running from ribs three to five to the coracoid process of the shoulder blade, and it moves the shoulder blade rather than the arm.
Do push-ups work the chest as well as a bench press?
They work the same muscle in the same pattern, but the load is capped by your body weight and your leverage. For someone untrained, push-ups are plenty; for someone strong, progression means changing leverage or adding external load.
Why does my chest hurt after a hard workout?
Delayed onset muscle soreness after unaccustomed work is common and settles within a few days. A sudden tearing sensation during a lift, bruising, or a visible change in the shape of the muscle is a different matter and needs assessment.
Nearby in this reference
Latissimus dorsi
The broad muscle of the back
Erector spinae
The columns of muscle either side of the spine
Deltoid
The cap of the shoulder
Rotator cuff
The four small muscles that hold the shoulder in its socket
Trapezius
The big diamond across the upper back and neck
Rhomboids
The straps that pull the shoulder blades together
All 34 body parts · Exercise library · Body map
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