Muscles of the Thoracic Wall

-- Muscle Origin Insertion NerveAction -- External intercostals Lower border of ribs Upper border of rib below Intercostal Elevate ribs in inspiration Internal intercostals Lower border of ribs Upper border of rib below Intercostal Elevate ribs (interchondral part); depress ribs Innermost intercostals Lower border of ribs Upper border of rib below Intercostal Elevate ribs Transversus thoracis Posterior surface of lower sternum and xiphoid Inner surface of costal cartilages 2–6 Intercostal Depresses ribs Subcostalis Inner surface of lower ribs near their angles Upper borders of ribs 2 or 3 below Intercostal Elevates ribs Levator costarum Transverse processes of T7 T11 Subjacent ribs between tubercle and angle Dorsal primary rami of C8 T11 Elevates ribs ◄.....Go back to the Gross Anatomy homepage