The muscles of the back 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 extrinsic back muscles are anatomically in the back, but they produce the movements of the shoulder and act as accessory respiratory muscles. They are the trapezius, latissimus dorsi, levator scapulae, rhomboids and serratus posterior muscles.
The intrinsic back muscles are considered as true back muscles, as their primary function is to produce the movements of the vertebral column (spine). Some notable synonyms for them are autochtonous back muscles and deep 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.
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