Muscles that act on the Back
The back is made up of many different muscles. These muscles allow us to bend, lift and twist our bodies in different directions.
Back muscles are organized into extrinsic (superficial) and intrinsic (deep) back muscles.
The intrinsic back muscles are often considered as true back muscles. They are separated from the superficial extrinsic layer by the thoracolumbar fascia.
The intrinsic back muscles consist of 3 layers:
- Superficial layer: splenius muscles, erector spinae muscles
- Deep layer: transversospinales (semispinalis, multifidus and rotatores)
- Deepest layer: interspinales and intertransversarii muscles
They are innervated by the dorsal rami of spinal nerves and act directly on the vertebral column.
In this section, you can learn the anatomy and actions of the back muscles, using interactive animations, diagrams, and illustrations. Memorize all the muscle facts with the help of muscle cheat sheets.