Iliocostalis Thoracis (Left) (Musculus iliocostalis thoracis)
Educational content only — not medical advice.
Anatomy
The intermediate thoracic continuation of the lateral erector spinae column, lying medial to the lumbar division. It consists of slender, flattened muscle bands that arise from the superior borders of the lower six ribs and run upward to attach to the upper six ribs and the transverse process of the seventh cervical vertebra. It acts to extend the thoracic spine and stabilize the posterior rib cage during heavy loading and forceful respiration.
Origin & insertion
From the superior borders of the angles of the lower six ribs (ribs 7–12), into the superior borders of the angles of the upper six ribs (ribs 1–6) and the transverse process of C7.
Action
Extends and laterally flexes the thoracic spine; helps depress the ribs during expiration.
Innervation
Posterior rami of thoracic spinal nerves (T1–T12).
Clinical notes
Trigger points and localized myofascial strain in the iliocostalis thoracis frequently mimic intercostal neuralgia or pleural pain on deep inspiration.
Related structures
Educational references
FAQ
What is the role of the Iliocostalis Thoracis (Left)?
The intermediate thoracic continuation of the lateral erector spinae column, lying medial to the lumbar division. It consists of slender, flattened muscle bands that arise from the superior borders of the lower six ribs and run upward to attach to the upper six ribs and the transverse process of the seventh cervical vertebra. It acts to extend the thoracic spine and stabilize the posterior rib cage during heavy loading and forceful respiration.
Why is the Iliocostalis Thoracis (Left) clinically important?
Trigger points and localized myofascial strain in the iliocostalis thoracis frequently mimic intercostal neuralgia or pleural pain on deep inspiration.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details