Quick Facts
Origin: Transverse processes of T1-T6 vertebrae.
Insertion: Spinous processes of C2-C5 vertebrae.
Action: Extends and rotates the neck at cervical vertebral joints.
Innervation: Medial branches of posterior rami of lower cervical and upper thoracic nerves.
Arterial Supply: Occipital, deep cervical, and vertebral arteries, dorsal branches of upper posterior intercostal arteries.
Related parts of the anatomy
Origin
The semispinalis colli muscle originates from the transverse processes of the first to sixth thoracic vertebrae. There can be variations between individuals regarding the origin sites for the semispinalis muscles (Tubbs, Shoja and Loukas, 2016).
Insertion
The fibers of the semispinalis colli muscle travel superiorly along the upper back and posterior neck regions and insert onto the spinous processes of the axis (second cervical vertebra) to fifth cervical vertebrae. There can be variations between individuals regarding the insertion sites for the semispinalis muscles (Tubbs, Shoja and Loukas, 2016).
Key Features & Anatomical Relations
Overall, the semispinalis muscles are the more superficial of the three muscles of the transversospinal muscles. They are intrinsic muscles of the back and are found along the upper back and posterior neck regions. They are long, flat skeletal muscles that are composed of three parts:
- semispinalis capitis, which is the superior portion;
- semispinalis colli, which is the middle portion;
- semispinalis thoracis, which is the large, inferior portion.
The semispinalis muscles are located:
- superficial to the suboccipital and multifidus muscles;
- deep to the trapezius, splenius capitis, splenius colli, and erector spinae muscles;
- medial to the levatores costarum breves and longi muscles;
- lateral to the interspinales muscles.
Actions
The semispinalis colli muscle is involved in multiple actions:
- during unilateral contraction, it rotates the neck to the opposite side at the cervical vertebral joints;
- during bilateral contraction, it extends the neck (Netter, 2011).
References
Netter, F. H. (2011) Atlas of Human Anatomy. Netter Basic Science Series: Saunders/Elsevier.
Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.
