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Chest muscle anatomy diagram
Muscle anatomy · Pectoralis major & minor

Chest anatomy

The chest is one fan-shaped muscle with fibres running in three directions — which is why it is trained as upper, middle and lower regions. Pressing with the arms at different angles shifts the load between them.

Jump to: Upper chest (clavicular head) · Middle chest (sternal head) · Lower chest (costal fibres)

Upper chest (clavicular head)

Fibres that start on the collarbone and run down and out to the arm. They lift the arm forward and up; incline angles load them most.

Dumbbell Incline Hammer Press — exercise demonstration
Dumbbell Incline Hammer Press

The Dumbbell Incline Hammer Press targets the upper part of the chest.

Barbell Incline Bench Press
Barbell Incline Bench Press

The Barbell Incline Bench Press primarily targets the upper portion of the chest muscles (pectoralis major), while also engaging the front shoulder (anterior deltoid) and triceps muscles.

Dumbbell Bench Press
Dumbbell Bench Press

The dumbbell bench press primarily targets the upper portion of the chest muscles, known as the clavicular head of the pectoralis major.

Dumbbell Incline Fly
Dumbbell Incline Fly

The dumbbell incline fly exercise primarily targets the upper portion of the chest muscles (pectoralis major).

Middle chest (sternal head)

The largest part, starting on the breastbone and running straight across to the arm. It pulls the arm across the body — flat pressing and flyes.

Barbell Bench Press — exercise demonstration
Barbell Bench Press

The barbell bench press primarily targets the middle and upper regions of the chest.

Lever Chest Press
Lever Chest Press

The Lever Chest Press primarily targets the middle portion of the chest, also known as the pectoralis major.

Lever Seated Fly
Lever Seated Fly

The Lever Seated Fly Chest exercise primarily targets the middle part of the chest (pectoralis major), as well as the front of the shoulders (anterior deltoids) and the triceps.

Cable Middle Fly
Cable Middle Fly

The Cable Middle Fly Chest exercise primarily targets the middle portion of the chest, also known as the sternal head of the pectoralis major muscle.

Lower chest (costal fibres)

The lowest fibres, rising from the ribs and upper abdominal wall. They pull the arm down and in — decline angles and dips.

Barbell Decline Bench Press — exercise demonstration
Barbell Decline Bench Press

The Barbell Decline Bench Press primarily targets the lower part of the chest, also known as the sternal or lower pecs.

Cable Low Fly
Cable Low Fly

The Cable Low Fly Chest exercise is primarily targeting the lower part of the chest muscles.

Dumbbell Decline Fly
Dumbbell Decline Fly

The dumbbell decline fly targets the lower part of the chest.

Chest Dip
Chest Dip

Chest dips primarily target the lower and outer portions of the chest muscles, also known as the pectoralis major.

Chest — common questions

Why does my upper chest lag? Most pressing happens flat or declined, which favours the sternal fibres. Add an incline press or incline flye early in the session, when you are freshest, and bring the elbows slightly forward at the top.
Can you isolate one chest region? Not fully — the whole pectoralis contracts in every press. You can only shift emphasis: incline for upper, flat for middle, decline or dips for lower.
How often should the chest be trained? Two sessions a week with 48–72 hours between them suits most people; total weekly volume matters more than any single session.
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Educational content — not medical advice. Exercise demonstrations and region data come from our apps' exercise library.

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