Deltoids - Muscle Physiology & Functional Anatomy

Anatomy

Origin:

• Anterior Deltoid

  • Anterior border & upper surface of the lateral third of the clavicle
    

• Lateral Deltoid

  • Surface of the lateral third of the clavicle
    

• Posterior Deltoid

  • Inferior edge of the spine of the scapula
    

Insertion:

• Anterior Deltoid

  • Deltoid tuberosity of the humerus
    

• Lateral Deltoid

  • Deltoid tuberosity of the humerous
    

• Posterior Deltoid

  • Deltoid tuberosity of the humerus
    

Major Arteries:

• Primarily posterior circumflex humeral artery

Neural Innervation:

• Axillary nerve (C5-C6)

Trigger Points:

Physiology

Concentric Functions:

• Anterior Deltoid

  • Shoulder abduction, flexion, transverse flexion & internal rotation
    

• Lateral Deltoid

  • Shoulder Abduction, flexion & transverse abduction
    

• Posterior Deltoid

  • Shoulder extension, transverse extension, transverse abduction & external rotation
    

Eccentric Functions:

• Anterior Deltoid

  • Decelerates shoulder extension & external rotation
    

• Lateral Deltoid

  • Assists in decelerating shoulder adduction
    

• Posterior Deltoid

  • Decelerates shoulder flexion, internal rotation & horizontal adduction
    

Isometric Function:

• Anterior Deltoid

  • Assists in dynamically stabilizing the glenohumeral joint during functional movements & works as a neutralizer during shoulder abduction
    

• Lateral Deltoid

  • Assists in dynamically stabilizing the glenohumeral joint during functional movements
    

• Posterior Deltoid

  • Assists in dynamically stabilizing the glenohumeral joint during functional movements and works as a neutralizer during shoulder abduction
    
    

Antagonists:

• Latissimus Dorsi
  

Exercises:

• Shoulder Exercise Videos

More Images of the Deltoids Muscle

More Information about the Deltoids Muscle

The deltoids muscle is almost always mentioned by one of its 3 heads which have varying functions. The name deltoids is derived from the Greek world 'delta' which means triangular.

The anterior deltoid is also known as the front deltoid or front shoulder.  The lateral deltoids are also known as the medial or side shoulder, deltoids or delts.  The posterior deltoids are also known as the rear shoulder, deltoids or delts.

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