3. Pectoralis Major

Origin:

• Clavicular head: anterior surface of the medial ½ of the clavicle
• Sterno-costal head: anterior surface of the sternum, costal cartilages of ribs 1-6

Insertion: Lateral lip of the bicipital groove of the humerus

Action:

• Adducts the humerus
• Medial rotates the humerus
• Positionally dependent: may extend the arm from a flexed position or flex the arm from an extended position

Innervation: Medial (C8-T1) and Lateral (C5/6/7) pectoral nerves

Needling

Position: Supine

Palpation: Pick up the bulk of this muscle on the anterior chest wall towards the axilla

Technique: Pick up the pectoralis muscle resting your fingers on the anterolateral aspect of the ribcage – Needle in an inferolateral direction away from the ribcage

Caution: High – the lung field lies directly under this muscle – Be mindful of your needling direction