Semispinalis

The semispinalis is a deep muscle of the back. It can be divided by its superior attachments into thoracic, cervicis, and capitis.

• Attachments: Originates from the transverse processes of C4 – T10. The fibres ascend 4 – 6 vertebral segments, attaching to the spinous processes of C2 – T4 and to the occipital bone of the skull.
• Actions: Extends and contralaterally rotates the head and the vertebral column.
• Innervation: Posterior rami of the spinal nerves
• Blood Supply:
  • Semispinalis thoracic receives its blood supply from the dorsal branches of posterior intercostal arteries.
  • Semispinalis cervicis receives its blood from the occipital, vertebral and deep cervical arteries.
  • Semispinalis capitis receives blood from the occipital artery.

By TeachMeSeries Ltd (2025)

Fig 1
The semispinalis and multfidus muscles.