Medial pectoral nerve

Dr Sarah Robertson and Dr Chamath Ariyasinghe et al.

The medial pectoral nerve, also known as the medial anterior thoracic nerve arises from the medial cord of the brachial plexus and supplies both the pectoralis minor and major muscles.

Gross anatomy

Origin

The medial pectoral nerve arises from the medial cord of the brachial plexus with fibers arising from the eighth cervical and first thoracic nerve roots.

Course

The medial pectoral nerve arises posterior to the axillary artery. It curves anteriorly to lie between the axillary artery and vein then, after receiving a communicating branch from the lateral pectoral nerve (the ansa pectoralis) enters the deep surface of the pectoralis minor muscle. The medial pectoral nerve perforates the pectoralis minor muscle and enters the deep surface of pectoralis major supplying the lower sternocostal fibers of the muscle.

Branches and supply

The medial pectoral nerve supplies both the pectoralis minor muscle and sternocostal portions of the pectoralis major muscle.

Relations

The medial pectoral nerve lies posterior to the axillary artery and anterior to the axillary vein. Along its course it receives a communicating branch from the lateral pectoral nerve to form a loop (ansa pectoralis) which runs anteriorly to both the axillary artery and vein.

Variant anatomy

The medial pectoral nerve may arise directly from the anterior division of the inferior trunk of the brachial plexus.

References

Anatomy: Upper limb

Anatomy: Upper limb

skeleton of the upper limb
- clavicle
  - conoid tubercle
  - supraclavicular foramen
- scapula
- humerus
  - supracondylar spur
  - olecranon foramen
- radius
- ulna
- carpal bones (mnemonic)
  - scaphoid
    - bipartite scaphoid
  - lunate
    - lunate morphology
  - triquetrum
  - pisiform
  - trapezium
  - trapezoid
  - capitate
  - hamate
  - variants
    - carpal coalition
      - lunotriquetral coalition
      - capito-hamate coalition
- metacarpals
- phalanges
  - terminal tuft
- accessory ossicles of the upper limb
  - accessory ossicles of the shoulder
    - os acromiale
  - accessory ossicles of the elbow
    - os supratrochleare dorsale
    - patella cubiti
  - accessory ossicles of the wrist (mnemonic)
    - os centrale carpi
    - os epilunate
    - os styloideum
    - os hamuli proprium
    - lunula
    - os triangulare
    - trapezium secondarium
    - os paratrapezium
    - os radiostyloideum (persistent radial styloid)
joints of the upper limb
- shoulder joint
  - articulations
  - associated structures
    - joint capsule
    - bursae
      - subacromial-subdeltoid (SASD) bursa
      - subscapular recess
      - subcoracoid bursa
      - coracoclavicular bursa
      - supra-acromial bursa
    - ligaments
      - coracoclavicular ligament
        
        conoid ligament
        
        trapezoid ligament
      - costoclavicular ligament
  - movements
    - scapulothoracic joint
      - scapular retraction (adduction)
      - scapular protraction (abduction)
      - scapular elevation
      - scapular depression
      - scapular lateral rotation
      - scapular medial rotation
    - glenohumeral joint
      - arm flexion
      - arm extension
      - arm abduction
      - arm adduction
      - arm internal rotation (medial rotation)
      - arm external rotation (lateral rotation)
      - circumduction
  - blood supply - scapular anastomosis
  - ossification centers
- elbow joint
  - proximal radioulnar joint
  - ligaments
    - medial (ulna) collateral ligament complex
    - lateral (radial) collateral ligament complex
  - associated structures
    - bicipitoradial bursa
    - olecranon bursa
  - movements
  - alignment
  - blood supply - elbow anastomosis
  - development
    - elbow ossification (mnemonic)
    - elbow ossification centers
- wrist joint
  - articulations
  - ligaments
    - intrinsic ligaments
    - extrinsic ligaments
  - associated structures
    - extensor retinaculum
    - flexor retinaculum
    - joint capsule
  - movements
  - alignment
    - carpal arcs
  - ossification
- hand joints
  - articulations
    - carpometacarpal joint
      - triscaphe joint
    - metacarpophalangeal joint
      - palmar ligament (plate)
      - collateral ligament
    - interphalangeal joint
      - palmar ligament (plate)
      - collateral ligament
  - movements
spaces of the upper limb
muscles of the upper limb
blood supply to the upper limb
- arteries
- veins
innervation of the upper limb
- intercostobrachial nerve
- brachial plexus (mnemonic)
  - branches from the roots
  - branches from the trunks
    - suprascapular nerve
  - branches from the cords
    - lateral cord
      - lateral pectoral nerve
    - posterior cord
    - medial cord
  - terminal branches
    - ulnar nerve
    - radial nerve
      - posterior interosseous nerve (deep radial nerve)
      - superficial radial nerve
    - musculocutaneous nerve
    - axillary nerve
    - median nerve
      - anterior interosseous nerve
      - bifid median nerve
lymphatic drainage of the upper limb
- axillary lymph nodes

Article information

rID: 37725

System: Musculoskeletal

Section: Anatomy

Tag: anatomy

Synonyms or Alternate Spellings:

Medial anterior thoracic nerve

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Cases and figures

Figure 1: Medial pectoral nerve Figure 1: Medial pectoral nerve

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Figure 2: brachial plexus Figure 2: brachial plexus

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