Serratus posterior inferior (Musculus serratus posterior inferior)
Educational content only — not medical advice.
Anatomy
A downward-fanning sheet from the lower thoracic and upper lumbar spine to ribs 9–12, opposing the superior muscle by fixing the lower ribs during forced inspiration.
Origin & insertion
Spinous processes of T11–L2 via the thoracolumbar fascia.
Action
Pulls ribs 9–12 backward and downward, widening the lower thorax in inspiration.
Innervation
Intercostal nerves T9–T11 and subcostal nerve (presumed).
Clinical notes
Its referred pain in the low back mimics erector-spinae strain; partially divided in posterior lumbar surgical approaches.
Related structures
Educational references
FAQ
What is the role of the Serratus posterior inferior?
A downward-fanning sheet from the lower thoracic and upper lumbar spine to ribs 9–12, opposing the superior muscle by fixing the lower ribs during forced inspiration.
Why is the Serratus posterior inferior clinically important?
Its referred pain in the low back mimics erector-spinae strain; partially divided in posterior lumbar surgical approaches.
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