The semispinalis muscle is one of the transversospinales muscles, which are a group of deep muscles within the back which lie deep to the erector spinae. There are three major muscle groups within the transversospinales: semispinalis, multifidus and rotares.
The semispinalis is the most superficial set of muscles in the transversospinales group and is comprised of three components: the semispinalis capitis, semispinalis cervicis, and the semispinalis thoracis.
Origin
- semispinalis thoracis: transverse processes of T6-10
- semispinalis cervicis: transverse processes of T1-5
- semispinalis capitis: transverse processes of C7-T6
Insertion
- semispinalis thoracis: spinous processes of C5-T4
- semispinalis cervicis: spinous processes of C2-C5
- semispinalis capitis: occiput
Action
- Extends the neck
- Rotates head to opposite side
Innervation
- Dorsal rami of cervical, and thoracic spinal nerves