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Pectoralis major

Contents

Anatomy

Position

  • Superficial

Origin

  • Clavicula, medial 1/2
  • 1.-7. costal cartilage
  • Sternum
  • The aponeurosis of the external obliquue muscle

Insertion

  • Crista tuberculi majus humeri

Main function

  • Shoulder
    • Adduction
    • Medial rotation
    • Flexion

Secondary function

  • Shoulder
    • Extension
    • Abduction
  • Scapula
    • Depression
    • Protraction
  • Trunk
    • Elevation (when arm is fixated)
    • Lateral deviation
    • Ipsilateral rotation

Nerve innervation

  • Segmental
    • C5-Th1
  • Peripheral
    • Medial and lateral pectoral nerves

Arterial supply

  • Pectoral branches of the thoracoacromial artery
  • Posterior intercostal artery
  • Lateral thoracal artery

Referred pain pattern

Muscle type

  • Upper - Postural
  • Lower - phasic
    • It's upper aspects play an important role as a postural muscle (during dysfunction it easily responds by becoming hypertonic)
    • It's lower aspects acts as a phasic muscle group (which weakens during dysfunction)

Symptoms

  • Pain along the medial aspect of the Scapula
  • Intense chest pain
  • Vascular thoracic outlet syndrome

Muscle attachment zones

Videos

Short version

Detailed version

Myofascial lines

Superficial ventral arm line

Supportive ventral line