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Muscles of the thoracic wall

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Notes

Muscles of the Thoracic Wall

Figure 1. A Posterior view and B antero-lateral view of muscles of the thoracic wall.
Figure 2. Antero-lateral view of A subcostal muscles (anterior portion of sternum and ribs dissected out), and B transversus thoracis muscle.
Figure 3. A Tissue cross section of two ribs and associated tissues. B Antero-lateral view of ribs and most superficial fascia.
Figure 4. Movement of ribcage and muscles of the thoracic wall during inhalation and exhalation.
Muscle
Proximal Attachment
Distal Attachment
Innervation
Action
Serratus posterior superior
  • Nuchal ligament & spinous processes of C7-T3 vertebrae
  • Superior borders of ribs 2-4
  • Ventral rami of intercostal nerves of T1-T5
  • Elevation of superior 4 ribs during inspiration
  • Role in proprioception
Serratus posterior inferior
  • Spinous processes of T11-L2 vertebrae
  • Inferior border of ribs 8-12
  • Ventral rami of intercostal nerves of T9-T12
  • Depressing inferior ribs
  • Role in proprioception
Levatores costarum
  • Transverse processes of C7-T11 vertebrae
  • Subjacent ribs between tubercle & angle
  • Lateral branch of posterior rami of thoracic spinal nerves
  • Elevate ribs
External intercostals
  • Inferior border of ribs above 
  • From tubercles of ribs posteriorly to costochondral junctions anteriorly
  • Superior border of rib below
  • Intercostal nerves traveling in respective intercostal space
  • Elevate ribs during forced inspiration
Internal intercostals
  • Inferior border of ribs above
  • From bodies of ribs & costal cartilages to sternum anteriorly & angles of ribs posteriorly
  • Superior border of rib below
  • Play a role during expiration
Innermost intercostals
  • Inferior border of ribs above
  • Deep to internal intercostals
  • Superior border of rib below
  • Play a role during expiration
Subcostals
  • Internal surface of lower ribs near angles
  • Superior border of 2nd-3rd rib
  • Intercostal nerves
  • Play a role during expiration
Transversus thoracis
  • Posterior surface of lower sternum
  • Internal surface of costal cartilages 2-6
  • Intercostal nerves
  • Slightly depress ribs during expiration
  • Might provide proprioceptive information
UNLABELLED DIAGRAMS

Sources

  1. "Clinically oriented anatomy" Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health (2014)
  2. "Dermatomes and dogma" Practical neurology 11.2 (2011)
  3. "Conflicting dermatome maps: educational and clinical implications." Journal of Orthopaedic & Sports Physical Therapy 41.6 (2011)

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