Structures

  • External intercostal
  • Internal intercostal
  • Innermost intercostal
  • Subcostales
  • Transversus thoracis
MuscleActionOriginInsertionInnervationBlood supply
External intercostalDuring Inspiration it;
- Supports intercostal space
- Elevates ribs superiorly
- Inferior margin of rib above- Superior surface of rib below- Intercostal nerves: T1-T11- Intercostal arteries
InternalintercostalDuring expiration it;
- Supports intercostal space
- Depresses ribs inferiorly
- Lateral part of costal groove of rib above- Superior surface of rib below Intercostal nerves: T1-T11- Intercostal arteries
Innermost intercostal- Acts with internal intercostals muscles- Medial part of costal groove of rib above- Internal portion of superior surface of rib below- Intercostal nerves: T1-T11- Intercostal arteries
Subcostales- Assist with depression of ribsInternal surface (near angle) of lower ribsInternal surface of second or third rib belowRelated inter-costal nerves- Intercostal arteries
Transversus thoracis- Depresses costal cartilages- Inferior part and internal surfaces of costal cartilages of ribs 2-6- Inferior portion body of sternum
- Xiphoid process
- Costal cartilages ribs 4-7
- Related inter-costal nerves- Intercostal arteries