Muscles of expiration -        Quite breathing- Elastic recoil of lung and chest wall. -        Forced expiration- o   Internal intercostal o   Intercostalis intimi o   Transversus thoracis o   Serratus posterior inferior o   Subcostalis o   Latissimus dorsi o   Abdominal muscles §  Rectus abdominis §  Transversus abdominis §  Internal oblique §  External oblique