Pectoralis Major Anatomy: Origin, Insertion, Actions, Innervation

Pectoralis Major Anatomy Study

Pectoralis Major Anatomy
Origin: Clavicular Head: Anterior surface of the medial half of the clavicle.
Sternal Head: Lateral aspects of the manubrium and body of the sternum, the upper six costal cartilages and the aponeurosis of the abdominal oblique
Insertion: Clavicular Head: Lateral lip of the bicipital groove of the humerus and anterior lip of the deltoid tuberosity
Sternal Head:
Lateral lip of the bicipital groove of the humerus and the anterior lip of the deltoid tuberosity.
Action: Shoulder flexion, Internal rotation, Adduction
Innervation: Medial pectoral nerve (C7, T1) and lateral pectoral nerve (C5, 6, 7)
Blood Supply: Pectoral branches from the thoraco-acromial artery

Synergist: Pectoralis minor, Subclavius, Serratus anterior, Trapezius, Latissimus dorsi, Rhomboid major and minor, Levator scapulae.

Antagonist: Deltoid, Supraspinatus, Infraspinatus, Teres major and minor, Subscapularis

Primary Actions: Clavicular Head

1. Adduction of the arm at the shoulder

  • Agonists: Latissimus Dorsi, Teres Major, Pectoralis Major (clavicular head), Triceps Brachii (long head)
  • Antagonists: Deltoid (middle fibers), Supraspinatus

2. Internal rotation of the arm at the shoulder

  • Agonists: Subscapularis, Deltoid (anterior ), Latissimus Dorsi, Pectoralis Major (clavicular head), Teres Major
  • Antagonists: Infraspinatus, Teres Minor, Deltoid (posterior)

3. Extension of the arm at the shoulder

  • Agonists: Latissimus Dorsi, Deltoid (posterior), Triceps Brachii (long head), Teres Major
  • Antagonists: Deltoid (anterior), Biceps Brachii, Coracobrachialis, Pectoralis Major (clavicular head)

 

Primary Actions: Sternal Head

1. Adduction of the arm at the shoulder

  • Agonists: Latissimus Dorsi, Teres Major, Pectoralis Major (clavicular head), Triceps Brachii (long head)
  • Antagonists: Deltoid (middle fibers), Supraspinatus

2. Internal rotation of the arm at the shoulder

  • Agonists: Subscapularis, Deltoid (anterior), Latissimus dorsi, pectoralis major (clavicular head), Teres Major
  • Antagonists: Infraspinatus, Teres Minor, Deltoid (posterior)

3. Extension of the arm at the shoulder

  • Agonists: Latissimus dorsi, Deltoid (posterior) Triceps brachii (long head), Teres Major
  • Antagonists: Deltoid (anterior), Biceps brachii, Coracobrachialis, Pectoralis Major (clavicular head)

For more information see: Pectoralis Major Pain and Symptoms


References:

The Trigger Point Therapy Workbook – Claire Davies, Amber Davies, and David G. Simons

Basic Clinical Massage Therapy: Integrating Anatomy and Treatment – James H. Clay and David M. Pounds

Trigger Point Therapy for Myofascial Pain – Donna Finando and Steven Finando

Massage Therapy Principles and Practice – Susan Salvo

Theory & Practice of Therapeutic Massage – Mark Beck

 

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