Masculoskeletal Gross Anatomy

• What is the origin of the Pectoralis major muscle?

  Clavicle, sternum, and upper six costal cartilages
• Where does the Pectoralis major muscle insert?

  Lateral lip of bicipital groove of humerus
• What is the nerve supply for the Pectoralis major muscle?

  Medial and lateral pectoral nerves from brachial plexus
• What are the nerve roots associated with the Pectoralis major muscle?

  C5, 6, 7, 8; T1
• What is the primary action of the Pectoralis major muscle?

  Adducts arm and rotates it medially; clavicular fibers also flex arm
• What is the origin of the Pectoralis minor muscle?

  3rd, 4th, and 5th ribs
• Where does the Pectoralis minor muscle insert?

  Coracoid process of scapula
• What is the nerve supply for the Pectoralis minor muscle?

  Medial pectoral nerve from brachial plexus
• What are the nerve roots associated with the Pectoralis minor muscle?

  C6, 7, 8
• What is the primary action of the Pectoralis minor muscle?

  Depresses point of shoulder; if the scapula is fixed, it elevates the ribs of origin
• What is the origin of the Subclavius muscle?

  1st costal cartilage
• Where does the Subclavius muscle insert?

  Clavicle
• What is the nerve supply for the Subclavius muscle?

  Nerve to subclavius from upper trunk of brachial plexus
• What are the nerve roots associated with the Subclavius muscle?

  C5, 6
• What is the primary action of the Subclavius muscle?

  Depresses the clavicle and steadies this bone during movements of the shoulder girdle
• What is the origin of the Serratus anterior muscle?


  Upper eight ribs
• Where does the Serratus anterior muscle insert?

  Medial border and inferior angle of scapula
• What is the nerve supply for the Serratus anterior muscle?

  Long thoracic nerve
• What are the nerve roots associated with the Serratus anterior muscle?

  C5, 6, 7
• What is the primary action of the Serratus anterior muscle?

  Draws the scapula forward around the thoracic wall; rotates scapula
• What are the key muscles connecting the upper limb to the thoracic wall and their actions?

  • Pectoralis major: Adducts arm, rotates it medially, flexes arm (clavicular fibers)
  • Pectoralis minor: Depresses shoulder, elevates ribs if scapula is fixed
  • Subclavius: Depresses clavicle, steadies clavicle during shoulder movements
  • Serratus anterior: Draws scapula forward, rotates scapula