Semispinalis - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x 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 (2026) Fig 1The semispinalis and multfidus muscles. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Frequent questions What is the semispinalis muscle? The semispinalis is a deep back muscle that is divided into three parts: thoracic, cervicis, and capitis. It plays a crucial role in extending and rotating the head and vertebral column. Where does the semispinalis muscle originate and attach? The semispinalis originates from the transverse processes of the cervical and thoracic vertebrae (C4 to T10) and ascends to attach to the spinous processes of C2 to T4 and the occipital bone of the skull. What actions does the semispinalis muscle perform? The semispinalis muscle is responsible for extending and contralaterally rotating both the head and the vertebral column. This function is essential for maintaining posture and facilitating head movement. How is the semispinalis muscle innervated? The semispinalis muscle is innervated by the posterior rami of the spinal nerves. This innervation is vital for its motor function and coordination during movement. What is the blood supply to the semispinalis muscle? The blood supply to the semispinalis varies by its sections: the thoracic part receives blood from the posterior intercostal arteries, the cervicis from the occipital, vertebral, and deep cervical arteries, and the capitis from the occipital artery. This vascular supply supports its metabolic needs and function. Rate This Article