[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) › Pectoralis major [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/) # Pectoralis major The pectoralis major is the large fan-shaped [chest](https://durgical.com/en/anatomy/region/chest/) muscle; it pulls the arm across the body, turns it inward and powers pushing. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=upper_limb&select=pectoralis_major&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The large fan-shaped chest muscle from the collarbone and breastbone to the [humerus](https://durgical.com/en/anatomy/humerus/). ## What it does Pulls the arm across the body and turns it inward; powers pushing. ## Key points - Forms the anterior wall of the axilla and, with its lower border, the anterior axillary fold - The deltopectoral groove between it and the front deltoid carries the cephalic vein up to the clavipectoral triangle, where the vein pierces the clavipectoral fascia - Its tendon is folded in two layers: the lowest sternocostal fibres twist to insert highest and deepest, the clavicular fibres lowest and most superficial - Absence of the sternocostal head is the core of Poland syndrome ## Key facts **Origin** Clavicular head: medial half of clavicle; sternocostal head: [sternum](https://durgical.com/en/anatomy/sternum/), [costal cartilages](https://durgical.com/en/anatomy/costal-cartilage/) 1–6, [external oblique](https://durgical.com/en/anatomy/external-abdominal-oblique-muscle/) aponeurosis **Insertion** Lateral lip of intertubercular sulcus (crest of greater tubercle) of humerus **Action** Adducts and medially rotates humerus; clavicular head flexes, sternocostal head extends from flexion **Nerve** Lateral pectoral nerve (C5–C7) and medial pectoral nerve (C8–T1) **Blood supply** Pectoral branch of [thoracoacromial artery](https://durgical.com/en/anatomy/thoracoacromial-artery/); perforating branches of [internal thoracic artery](https://durgical.com/en/anatomy/internal-thoracic-artery/) ## Relations **Superficial** The breast on the [pectoral fascia](https://durgical.com/en/anatomy/pectoral-fascia/), separated by the loose retromammary space; [skin](https://durgical.com/en/anatomy/skin/) **Deep** [Pectoralis minor](https://durgical.com/en/anatomy/pectoralis-minor-muscle/), [subclavius](https://durgical.com/en/anatomy/subclavius/) and the clavipectoral fascia; lower down the [ribs](https://durgical.com/en/anatomy/ribs/), intercostal muscles and [serratus anterior](https://durgical.com/en/anatomy/serratus-anterior/) **Lateral** [Front deltoid](https://durgical.com/en/anatomy/deltoid-anterior-part/) across the deltopectoral groove, with the [cephalic vein](https://durgical.com/en/anatomy/cephalic-vein/) **Above** The [clavicle](https://durgical.com/en/anatomy/clavicle/); the clavipectoral (deltopectoral) triangle opens between the clavicle, its clavicular head and the deltoid **Below** Its free lower border, the anterior axillary fold, overlying the axillary lymph nodes ## How to find it Pressing the hands together in front of the chest contracts the whole muscle. Resisted horizontal adduction with the arm forward at 90° brings out the clavicular head; resisted adduction down toward the opposite hip brings out the sternocostal head. The anterior axillary fold can be gripped between thumb and fingers. ## Examination - Clavicular head (lateral pectoral nerve): resisted horizontal adduction from 90° of flexion; sternocostal head ([medial and lateral pectoral nerves](https://durgical.com/en/anatomy/medial-and-lateral-pectoral-nerves/)): resisted adduction from abduction; isolated weakness of one head localises a pectoral nerve or root lesion ## On imaging MRI is best for tears: axial and oblique coronal images follow the tendon to its insertion lateral to the bicipital groove; the classic injury is avulsion of the lower sternal fibres while bench pressing. Ultrasound is a quick first check of tendon continuity and haematoma. On a chest radiograph, its absence (Poland syndrome) or a mastectomy makes that side look darker. ## Common problems - Tendon rupture, usually during a heavy bench press: a pop, bruising and a changed chest contour. - Muscle strains. ## How it is diagnosed Exam of the armpit fold and pushing strength. MRI shows where and how much it is torn. ## Treatment - Surgical repair of the tendon to the humerus for active people. - Without surgery for partial tears and muscle strains. ## Clinical notes - Pedicled pectoralis major flap on the pectoral branch of the thoracoacromial artery: a classic reconstruction for [head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) defects - Breast examination with the hands pressed on the hips tenses the muscle; a lump that becomes fixed suggests a tumour attached to the pectoral fascia or muscle - The [pectoralis major tendon](https://durgical.com/en/anatomy/pectoralis-major-tendon/) transfer is used for irreparable [subscapularis](https://durgical.com/en/anatomy/subscapularis/) tears ## Anatomical variants - Heads may be more or less separate and attachments vary; the sternocostal head may be missing (Poland syndrome, sometimes with hand anomalies on the same side) - A sternalis muscle, a vertical strip over the sternum, is a related variant that can look like a mass on mammography ## Development It begins next to the arm bud at lower cervical levels and migrates over the front of the chest, bringing its [brachial plexus](https://durgical.com/en/anatomy/roots-of-brachial-plexus/) nerves with it; failure of the sternocostal head to form is the basis of Poland syndrome. ## Memory aid The medial pectoral nerve lies lateral to the lateral pectoral nerve: they are named for their cords, not their position. ## Related conditions - [Costochondritis](https://durgical.com/en/conditions/costochondritis/) - [Gynaecomastia](https://durgical.com/en/conditions/gynaecomastia/) - [Breast cancer](https://durgical.com/en/conditions/breast-cancer/) ## Test yourself Think of the answer, then tap the question to see it. ## What is the nerve supply of the two heads of the pectoralis major? Clavicular head: lateral pectoral nerve; sternocostal head: medial and lateral pectoral nerves. ## Which structure runs in the deltopectoral groove, and where does it go? The cephalic vein, up to the clavipectoral triangle, where it pierces the clavipectoral fascia. ## Where does the pectoralis major insert, and what are its main actions? On the lateral lip of the intertubercular sulcus; it adducts and medially rotates the humerus. ## Absence of which part of the pectoralis major is the core of Poland syndrome? The sternocostal head. ## What vessel does a pedicled pectoralis major flap rely on? The pectoral branch of the thoracoacromial artery; a classic flap for head and neck defects. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/pectoralis-major-muscle/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** musculus pectoralis major TA2 2301 **Official Spanish (DeCS)** Músculo pectoral mayor **English (TA2)** Pectoralis major ## Related - [Cephalic vein](https://durgical.com/en/anatomy/cephalic-vein/) - [Interpectoral nodes](https://durgical.com/en/anatomy/interpectoral-nodes/) - [Pectoral nerves](https://durgical.com/en/anatomy/medial-and-lateral-pectoral-nerves/) - [Thoracoacromial artery](https://durgical.com/en/anatomy/thoracoacromial-artery/) - [Lateral thoracic artery](https://durgical.com/en/anatomy/lateral-thoracic-artery/) - [Clavicle](https://durgical.com/en/anatomy/clavicle/) - [Manubrium](https://durgical.com/en/anatomy/manubrium-of-sternum/) - [Pec major tendon](https://durgical.com/en/anatomy/pectoralis-major-tendon/) Sources: Terminologia Anatomica (TA2); [Anatomy, Shoulder and Upper Limb, Pectoral Muscles](https://www.ncbi.nlm.nih.gov/books/NBK545241/); Anatomy of the Human Body (20th ed.): Development of the Muscles (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/pectoralis-major-muscle/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/pectoralis-major-muscle/