Pectoralis Major

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Schematic of Pectoralis major and coracobrachialis¹
1: Pectoralis Major (clavicular part)
2: Pec Major (Sternocostal part)
3: Pec Major (abdominal part)
4: Coracobrachialis

Pectoralis Major and Coracobrachialis, anterior view¹

Muscle	Origin	Insertion	Innervation	Action
Pectoralis major	Clavicle (medial half) Sternum Costal cartilages 1-6 Rectus sheath (anterior layer)	Humerus (crest of greater tubercle)	Lateral pectoral n. Medial pectoral n. C5 - T1	Entire muscle: Adduction, IR Clavicular & Sternocostal parts: Flexion, Aids in respiration when shoulder is fixed

Origin

• Clavicular part: Clavicle (medial half)¹
• Sternocostal part: sternum, costal cartilages 1–6¹
• Abdominal part: rectus sheath (anterior layer)¹

Note

Manubrium and the aponeurosis of the external oblique are potential originations of the pectoralis major

Insertion

Humerus (crest of greater tubercle)¹

Innervation

• Lateral pectoral nerve¹
• Medial pectoral nerve¹
• (C5, C6, C7, C8, T1)¹

Action

• Entire muscle: GHJ Adduction, Internal rotation¹
• Clavicular and sternocostal parts: Flexion; assist in respiration when shoulder is fixed¹

Entire muscle: GHJ Adduction, Internal rotation

Clavicular and sternocostal parts: Flexion; assist in respiration when shoulder is fixed

Length test

• PEctoralis major contracture test (hands behind head)

Muscle-to-tendon Surgery

• Worse prognosis than tendon-to-bone because of slow healing

Tendon-to-bone Surgery

considerations

• Thoracic spine mobility
• Grip strength
• light cardio
• contralateral limb training (go light just to be safe to avoid irradiation)

Exercises

• Elbow CARs
• Spine CARs

References

1.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.