Erector spinae
Spinal erectors · Back
- Origin
- Sacrum, iliac crest and spinous processes of the lumbar vertebrae
- Insertion
- Ribs, transverse and spinous processes of the vertebrae, and the skull
- Action
- Extends and laterally flexes the spine
Three columns of muscle (iliocostalis, longissimus, spinalis) running along the spine. They hold the back straight under load in squats and deadlifts and extend it in back extensions.