The serratus posterior superior is a muscle within the intermediate compartment of the back. It is a thin and rectangular in shape, and lies deep to the rhomboid muscles in the upper back. Attachments: Originates from the lower part of the ligamentum nuchae, and the cervical and thoracic spines (usually C7 – T3). The muscle fibres run in an inferolateral direction, attaching to ribs 2 – 5. Actions: Elevates ribs 2 – 5. Innervation: Intercostal nerves T2 – T5. Blood Supply: Posterior intercostal arteries. Adobe Stock, Licensed to TeachMeSeries Ltd Fig 1The intermediate back muscles; serratus posterior superior and inferior. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Print Article Rate This Article