Pectoralis Major Muscle Anatomy

Overview
Origin The anterior surface and the medial half of clavicle
The anterior surface of sternum
The superior six costal cartilages
Aponeurosis of the external oblique muscle
Insertion The lateral lip of the bicipital groove
Action Humeral adduction
Humeral medial rotation
Humeral flexion (clavicular head)
Humeral extension (sternocostal head)
Nerve Medial and lateral pectoral nerves (C5-T1)
Artery Pectoral branch of the thoracoacromial trunk

Location & Overview

The pectoralis major is a muscle which makes up the bulk of the chest. It is sometimes referred to as the ‘pecs’. It is a fan shaped muscle which lies atop of the pectoralis minor and serratus anterior muscles. The pectoralis major is commonly divided into two heads when describing it. The clavicular head (which is comprised of the superior portion closest to the clavicle) and the sternocostal head (which is the inferior portion originating from the sternum) [1] [2] [3].

pectoralis major muscle

Pictured here we can see the pectoralis major muscle.

Origin & Insertion

The pectoralis major originates from the anterior surface of the medial half of the clavicle, the anterior surface of the sternum, the superior six costal cartilages and the aponeurosis of the external oblique muscle. It then inserts at the lateral lip of humerus’s bicipital groove (also known as the intertubercular groove) [4] [5] [6].

origins of the pectoralis major muscle

Here we can see the origins of the pectoralis major muscle at the anterior surface and the medial half of clavicle, the anterior surface of sternum and the superior six costal cartilages.

insertion of the pectoralis major muscle

Here we can see the insertion of the pectoralis major muscle at the lateral lip of the bicipital groove.

Actions

The pectoralis major’s actions are: humeral adduction, medial rotation of the humerus, the clavicular head can cause flexion of the humerus and the sternocostal head can cause extension of the humerus [7] [8].

Innervation

The pectoralis major is innervated by the medial and lateral pectoral nerves (C5-T1) [9].

Blood Supply

Blood is supplied from the pectoral branch of the thoracoacromial trunk [10].

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Pectoralis Major Flashcards

References

References
1 Haley CA, Zacchilli MA. Pectoralis major injuries: evaluation and treatment. Clin Sports Med. 2014 Oct;33(4):739-56. doi: 10.1016/j.csm.2014.06.005. PMID: 25280620.
2 Sanchez ER, Sanchez R, Moliver C. Anatomic relationship of the pectoralis major and minor muscles: a cadaveric study. Aesthet Surg J. 2014 Feb;34(2):258-63. doi: 10.1177/1090820X13519643. Epub 2014 Jan 8. PMID: 24402060.
3, 6 Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.
4, 7, 9, 10 Solari F, Burns B. Anatomy, Thorax, Pectoralis Major Major. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525991/
5, 8 Baig MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Pectoral Muscles. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545241/