Pectoralis Major - Muscle Physiology & Functional Anatomy

Anatomy

Origin:

• Sternal head

  • Anterior surface of the sternum, the superior six costal cartilages (2nd to 6th ribs), and the aponeurosis of the external oblique muscle
    

• Clavicular head

  • Anterior surface of the medial half of the clavicle.
    

Insertion:

• Sternal head

  • Intertubercular groove of the proximal, anterior humerus 
    

• Clavicular head

  • Intertubercular groove of the proximal, anterior humerus 
    

Major Arteries:

• Pectoral branch of the thoracoacromial (trunk) artery

Neural Innervation:

• Sternal head

  • Lateral & medial pectoral nerves C7-C8 & T1
    

• Clavicular head

  • Lateral & medial pectoral nerves C5-C6

Trigger Points:

Physiology

Concentric Functions:

• Sternal head

  • Transverse flexion, adduction, internal rotation, adduction & extension of the shoulder
    

• Clavicular head

  • Transverse flexion, adduction, internal rotation, adduction, flexion & abduction of the shoulder 

Eccentric Functions:

•  Decelerates shoulder extension, horizontal abduction and external rotation

Isometric Function:

• Assists in dynamically stabilizing the shoulder complex during overhead movements

Related Muscles

• Pectorlis Minor

Antagonists:

• Latissimus dorsi
• Many others depending on motion

Exercises:

• Chest Exercise Videos

Back to Functional Anatomy Chart

More Images of the Pectoralis Major Muscle

More Information about the Pectoralis Major Muscle