Pectoralis Minor Anatomy

Pectoralis Minor Muscle

Origin: Anterior surfaces of the third to fifth ribs
Insertion: The medial aspect of the coracoid process of the scapula.
Actions: Scapula protraction, depression of the scapula
Innervation: Medial pectoral nerve (C7, T1)
Blood Supply: Branches from the thoraco-acromial artery

Primary Actions of the Pectoralis Minor

1. Protraction of the scapula

Agonists:

  • Adductor magnus (anterior part)
  • Adductor longus

Antagonists:

  • Gluteus maximus (upper fibers)
  • Gluteus medius
  • Gluteus minimus

2. Depression of the scapula

Agonists:

  • Serratus Anterior (lower part)
  • Trapezius (lower part)

Antagonists: 

  • Trapezius (upper part)
  • Levator scapulae

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Secondary Actions of the Pectoralis Minor

1. Assists with downward rotation of the scapula

Agonists:

  • Levator Scapulae
  • Serratus Anterior (upper fibers)
  • Rhomboid Major
  • Rhomboid Minor
  • Trapezius (middle fibers)

Antagonists: 

  • Trapezius (upper and lower fibers)
  • Serratus Anterior (lower fibers)