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Pectoralis minor

Contents

Anatomy

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page

Position

  • Deep

Origin

  • 3-5th ribs

Insertion

  • Processus coracoideus scapula

Main function

  • Scapula
    • Protraction
    • Depression
  • 3-5th ribs
    • Elevation

Secondary function

  • Scapula
    • Downward rotation

Nerve innervation

  • Segmental
    • C5-Th1
  • Peripheral
    • Medial pectoral nerve
    • Lateral pectoral nerve

Arterial supply

  • Pectoral branch of thoracoacromial artery
  • Posterior intercostal artery
  • Lateral thoracic artery

Palpation

  • Patient position
    • Supine
  • Support the patient's arm in abduction and localize the lateral limitation of pectoralis major
  • Place fingers deep to the pectoralis major and press them medially from the lateral side
    • The medial aspect of pectoralis minor can be felt in towards the ribs
  • To distinguish the pectoralis minor further, ask the patient to take a deep breath
    • This will lead to the pectoralis minor tightening since it leads to elevation of the 3-5th ribs without the adjacent muscles becoming tight

Muscle length test

  • Patient position
    • Supine
  • The patient is lying with arms along the side of the body with the palms turned up towards the ceiling, elbows extended, knees flexed and the lower back in full contact with the bench
  • Observe the position of the patient's shoulder while you are standing on the same side as the head of the patient while he/she is lying on the bench
  • If the shoulders are in contact with the bench the muscle is considered to be of adequate length

Strength test

  • Patient position
    • Supine
  • Ask the patient to push the shoulders forward (protraction). Make sure that the patient isn't using the arms to compensate during the execution
  • Place resistance towards the anterior aspect of the shoulder in a downward direction towards the bench