The chest muscle

What it does

The pectoralis major fans out from the collarbone, breastbone and upper ribs and narrows to a tendon on the front of the humerus. It pulls your arm across your body, rotates it inwards and pushes it forward, as in a hug, a push-up or a punch. Its lower edge forms the front fold of your armpit.

Why it matters

Climbing, pushing and throwing all depend on this muscle. Weightlifters can tear its tendon during a heavy bench press, an injury that often needs surgery.

Nearby

• The pectoralis minor
• The breastbone
• The collarbone
• The upper arm bone
• The boxer's muscle

Read more

• Pectoralis major — Wikipedia