Important structures that pass between the subclavius and pectoralis minor muscles include the cephalic vein, the thoraco-acromial artery, and the lateral pectoral nerve.
The lateral thoracic artery leaves the axilla by passing through the fascia inferior to the pectoralis minor muscle.
The medial pectoral nerve leaves the axilla by penetrating directly through the pectoralis minor muscle to supply this muscle and to reach the pectoralis major muscle.