• Subscapularis
  • Teres major
  • Latissimus dorsi
  • Deltoid
  • Pectoralis major

MuscleActionOriginInsertionInnervationBlood supply
Subscapularis- Medially rotates arm
- Adducts arm
- assists in stabilisation of glenohumeral joint
- Subscapular fossa of scapula- Lesser tubercle of humerus- Upper and lower subscapular nerves: C5,6,7- Subscapular artery
Teres Major- Adduction of humerus
- Medial rotation of humerus
- Extension of humerus
- Inferior angle of scapula- Medial portion of intertubercular groove of humerus- Lower subscapular nerve: C5,6,7- Sub scapular artery
- Cicumflex scapular artery
Latissimus dorsi- Extends humerus
- Depress scapula
- Adducts humerus
- Medially rotates humerus
- Spinous processes of T7-L5
- Sacrum
- Iliac crest
- Ribs 10-12
- Biccipital groove of humerus-Thoracodorsal nerve: C6-8- Thoracodorsal branch of subscapular artery
Deltoid- Anterior fibres: Flexion of arm
- Middle fibres: abduction of arm
- Posterior fibres: Extension of arm
- clavicle
- Acromion process
- Spine of scapula
- Deltoid tuberosity- Axillary nerve: C5,6- Deltoid branch of thoracoacromial artery
Pectoralis major- Adduction humerus
- Medial rotation humerus
- Flexion of the humerus
- Medial 1/2 of clavicle
- Anterior surface of sternum
- Costal cartilages 1-7
- Aponeurosis of external oblique
- Proximal humerus (lateral intertubercular groove)- Medial and lateral pectoral nerves- Pectoral branch of the thoracoacromial trunk