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Origin Insertion Nerve Supply of Pectoralis Major

Last updated: February 7, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 3 min read

Origin Insertion nerve Supply of Pectoralis Major/Pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla. Its origin lies anterior surface of the medial half of the clavicle, the anterior surface of the sternum, the first 7 costal cartilages, the sternal end of the sixth rib, and the aponeurosis of the external oblique of the anterior abdominal wall. The insertion of the pectoralis major is at the lateral lip of the intertubercular sulcus of the humerus. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin. The sternocostal head is described as having between 2 to 7 distinct segments.

Origin Insertion Nerve Supply of Pectoralis Major

Structure and Function of Pectoralis Major

The function of the pectoralis major is 3-fold and dependent on which heads of muscles are involved.

  • Flexion, adduction and medial rotation of the arm at the glenohumeral joint
  • Clavicular head causes flexion of the extended arm
  • Sternoclavicular head causes extension of the flexed arm

The pectoralis major shows variation in muscle fiber length, differing from the majority of muscle fibers in the human body, which usually show uniform length. This configuration of the muscle fibers potentially allows for more power production through differing muscle shortening velocities.

Nerves of Pectoralis Major

The 2 heads of the pectoralis major have different nervous supplies. The clavicular head derives its nerve supply from the lateral pectoral nerve. The medial pectoral nerve innervates the sternocostal head. The lateral pectoral nerve arises directly from the lateral cord of the brachial plexus, and the medial pectoral nerve arises from the medial cord.

Anatomy of the Pectoralis Major

  • Origin – Clavicular head, anterior sternum, costal cartilages 1 to 7, the sternal end rib 6, aponeurosis of the external oblique
  • Insertion – Lateral lip intertubercular sulcus of the humerus
  • Nervous innervation – Medial and lateral pectoral nerves (clavicular head C5, sternocostal head C6/7/8, T1)
  • Function – Flexion, adduction, and medial rotation of the arm at the glenohumeral joint; clavicular head causes flexion of the extended arm; sternoclavicular head causes extension of the flexed arm
  • Arterial supply – Pectoral artery (thoracoacromial trunk, the second branch of the axillary artery)
  • Venous drainage – Pectoral vein (drains into the subclavian vein)


References

Origin Insertion Nerve Supply of Pectoralis Major


Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.