Quick Facts
Origin: Angles of third to sixth ribs.
Insertion: Posterior tubercles of transverse processes of C4-C6 vertebrae.
Action: Extends and laterally flexes neck at cervical vertebral joints.
Innervation: Lateral branches of posterior rami of lower cervical and upper thoracic nerves.
Arterial Supply: Occipital, deep cervical, and vertebral arteries, and dorsal branches of upper posterior intercostal arteries.
Related parts of the anatomy
Origin
The iliocostalis colli muscle originates from the angles of the third to sixth ribs. There can be variations between individuals regarding the origin sites for the iliocostalis colli muscle (Tubbs, Shoja and Loukas, 2016).
Insertion
The fibers of the iliocostalis colli muscle travel superomedially along the posterior neck region and insert onto the posterior tubercles of the transverse processes of fourth to sixth cervical vertebrae. There can be variations between individuals regarding the insertion sites for the iliocostalis colli muscle (Tubbs, Shoja and Loukas, 2016).
Key Features & Anatomical Relations
Overall, the iliocostalis muscles are one of the three muscles of the erector spinae. They are intrinsic muscles of the back and are found along the entire length of the back and posterior neck regions. They are long, flat skeletal muscles that are composed of three parts:
- iliocostalis colli, which is the superior portion;
- iliocostalis thoracis, which is the middle portion;
- iliocostalis lumborum, which is the inferior portion.
The iliocostalis muscles are located:
- superficial to the ribs, and the external intercostal and quadratus lumborum muscles;
- deep to the serratus posterior superior, rhomboid major, trapezius, latissimus dorsi, and serratus posterior inferior muscles, and the thoracolumbar fascia;
- lateral to the longissimus muscle.
Actions
The iliocostalis colli muscle is involved in multiple actions:
- during unilateral contraction, it laterally flexes the neck to the same side at the cervical vertebral joints;
- during bilateral contraction, it extends the neck at the cervical vertebral joints (Moore, Dalley and Agur, 2009).
References
Moore, K. L., Dalley, A. F. and Agur, A. M. R. (2009) Clinically Oriented Anatomy. Lippincott Williams & Wilkins.
Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.
