Muscles/Shoulder

Shoulder

deltoid

DEL-toyd

The deltoid is the rounded shoulder cap muscle with anterior, middle, and posterior fibers covering the shoulder joint. It abducts, flexes, and extends the arm for raises and presses. Builds the V-taper and protects the rotator cuff.

Open in 3D Viewer

Common Pain & Injury

Shoulder soreness or impingement pain with overhead moves. Night pain or weakness needs PT or doc.

Anatomy & Function

Origin

Clavicle, acromion, spine of scapula (collarbone, shoulder peak, blade ridge)

Insertion

Deltoid tuberosity of humerus (mid outer arm bone)

Actions

Arm abduction (side raise)
Anterior: flexion (front raise)
Posterior: extension (rear delt)

Innervation

Axillary nerve (C5-C6)

Muscle Relationships

Antagonists

Latissimus dorsi (for abduction)

Synergists

Supraspinatus (abduction)Pectoralis major (flexion)

Trigger Points

Anterior: refers to upper arm; Middle: shoulder blade; Posterior: elbow.

Stretches

1Cross-body delt stretch

2Overhead triceps stretch (anterior)

3Rear delt doorway stretch

Common Conditions

Deltoid strainSubacromial impingementRotator cuff tendinopathy

Anatomical Parts

Acromial part of left deltoidClavicular part of right deltoidSpinal part of left deltoidSpinal part of right deltoidAcromial part of right deltoidClavicular part of left deltoid

FAQ

What does deltoid do?

Abducts, flexes, extends arm for all shoulder raises.

Why do my delts hurt?

Overuse or impingement from presses; check form.

Deltoid stretch?

Cross arm over chest for side delts.

Deltoid tear symptoms?

Sudden pain, weakness, bruising in shoulder.

Exercises for deltoid

20

Alternating Cable Shoulder Press position 1

Alternating Cable Shoulder Press position 2

Alternating Cable Shoulder Press

beginner·cable

Alternating Deltoid Raise position 1

Alternating Deltoid Raise position 2

Alternating Deltoid Raise

beginner·dumbbell

Alternating Kettlebell Press position 1

Alternating Kettlebell Press position 2

Alternating Kettlebell Press

intermediate·kettlebells

Anti-Gravity Press position 1

Anti-Gravity Press position 2

Anti-Gravity Press

beginner·barbell

Arm Circles position 1

Arm Circles position 2

Arm Circles

Arnold Dumbbell Press position 1

Arnold Dumbbell Press position 2

Arnold Dumbbell Press

intermediate·dumbbell

Back Flyes - With Bands position 1

Back Flyes - With Bands position 2

Back Flyes - With Bands

beginner·bands

Backward Medicine Ball Throw position 1

Backward Medicine Ball Throw position 2

Backward Medicine Ball Throw

beginner·medicine ball

Band Pull Apart position 1

Band Pull Apart position 2

Band Pull Apart

beginner·bands

Barbell Incline Shoulder Raise position 1

Barbell Incline Shoulder Raise position 2

Barbell Incline Shoulder Raise

beginner·barbell

Barbell Rear Delt Row position 1

Barbell Rear Delt Row position 2

Barbell Rear Delt Row

beginner·barbell

Barbell Shoulder Press position 1

Barbell Shoulder Press position 2

Barbell Shoulder Press

intermediate·barbell

Battling Ropes position 1

Battling Ropes position 2

Battling Ropes

beginner·other

Bent Over Dumbbell Rear Delt Raise With Head On Bench position 1

Bent Over Dumbbell Rear Delt Raise With Head On Bench position 2

Bent Over Dumbbell Rear Delt Raise With Head On Bench

beginner·dumbbell

Bent Over Low-Pulley Side Lateral position 1

Bent Over Low-Pulley Side Lateral position 2

Bent Over Low-Pulley Side Lateral

beginner·cable

Bradford/Rocky Presses position 1

Bradford/Rocky Presses position 2

Bradford/Rocky Presses

beginner·barbell

Cable Internal Rotation position 1

Cable Internal Rotation position 2

Cable Internal Rotation

beginner·cable

Cable Rear Delt Fly position 1

Cable Rear Delt Fly position 2

Cable Rear Delt Fly

beginner·cable

Cable Rope Rear-Delt Rows position 1

Cable Rope Rear-Delt Rows position 2

Cable Rope Rear-Delt Rows

beginner·cable

Cable Seated Lateral Raise position 1

Cable Seated Lateral Raise position 2

Cable Seated Lateral Raise

beginner·cable

Also Works deltoid

10

Ab Roller position 1

Ab Roller position 2

Ab Roller

intermediate·other

Advanced Kettlebell Windmill position 1

Advanced Kettlebell Windmill position 2

Advanced Kettlebell Windmill

intermediate·kettlebells

Alternating Floor Press position 1

Alternating Floor Press position 2

Alternating Floor Press

beginner·kettlebells

Around The Worlds position 1

Around The Worlds position 2

Around The Worlds

intermediate·dumbbell

Barbell Ab Rollout position 1

Barbell Ab Rollout position 2

Barbell Ab Rollout

intermediate·barbell

Barbell Ab Rollout - On Knees position 1

Barbell Ab Rollout - On Knees position 2

Barbell Ab Rollout - On Knees

expert·barbell

Barbell Bench Press - Medium Grip position 1

Barbell Bench Press - Medium Grip position 2

Barbell Bench Press - Medium Grip

beginner·barbell

Barbell Guillotine Bench Press position 1

Barbell Guillotine Bench Press position 2

Barbell Guillotine Bench Press

intermediate·barbell

Barbell Incline Bench Press - Medium Grip position 1

Barbell Incline Bench Press - Medium Grip position 2

Barbell Incline Bench Press - Medium Grip

beginner·barbell

Barbell Rollout from Bench position 1

Barbell Rollout from Bench position 2

Barbell Rollout from Bench

intermediate·barbell

Related Shoulder Muscles

infraspinatus muscle

Infraspinatus caps the back of the shoulder blade, externally rotating the arm for throwing and serving. Key rotator cuff muscle for shoulder stability in presses and pulls.

The subscapularis is the anterior rotator cuff muscle filling the scapula's subscapular fossa. It internally rotates the arm and stabilizes the shoulder joint. Crucial for fitness in presses, pulls, and preventing dislocations.

The supraspinatus tops the rotator cuff on scapula's fossa, initiating shoulder abduction. Vital for overhead presses and impingement prevention in weight training.

The teres major is a thick muscle from lower scapula to humerus, adducting and internally rotating the arm. 'Lat's little helper' for pulling exercises like rows and pull-ups.

The teres minor is a narrow rotator cuff muscle on scapula's lateral border, externally rotating and stabilizing the shoulder. Key for throwing and pressing without winging.

Shoulder Pain Guide

Common causes and relief

Activities & Sports

See which activities use deltoid