Semispinalis thoracis
Back
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Transverse processes of T6 to T10
- Insertion
- Spinous processes of C6 to T4
- Action
- Extends the thoracic spine and turns it to the opposite side
- Nerve supply
- Dorsal rami of the spinal nerves
The lowest part of the semispinalis, deep in the upper back under the erector spinae. Each slip spans several vertebrae, helping extend and twist the upper back.
Semispinalis thoracis anatomy page →