Iliocostalis Cervicis
Back · Trunk
The iliocostalis cervicis is the cervical portion of the iliocostalis column, the most lateral of the three subdivisions of the erector spinae. It arises from the angles of ribs 3 to 6 and ascends to insert on the posterior tubercles of the transverse processes of C4 to C6, thereby extending the erector spinae mass up into the neck. Acting on both sides it extends the cervical spine, and acting on one side it laterally flexes the neck toward that side. Like the rest of the deep back muscles it is supplied by the posterior (dorsal) rami of the cervical spinal nerves.
Origin, Insertion, Action & Nerve
Origin
Angles of ribs 3–6
Insertion
Posterior tubercles of the transverse processes of C4–C6
Action
Bilaterally extends the cervical spine; unilaterally laterally flexes it
Nerve
Posterior (dorsal) rami of cervical spinal nerves
Attachments explained
The Iliocostalis Cervicis is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Angles of ribs 3–6
Insertion
Posterior tubercles of the transverse processes of C4–C6
Action & function
When the Iliocostalis Cervicis contracts, it produces the following movements: Bilaterally extends the cervical spine; unilaterally laterally flexes it.
As part of the Back group of the Trunk, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Iliocostalis Cervicis receives its nerve supply from the Posterior (dorsal) rami of cervical spinal nerves.
Because a muscle can only contract when its nerve is intact, injury to the Posterior can weaken or paralyse the Iliocostalis Cervicis, impairing the movements it normally produces (bilaterally extends the cervical spine). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Iliocostalis Cervicis (the OIANS method)
Place iliocostalis cervicis as the neck segment of the most lateral erector spinae column, running from the upper ribs to the cervical transverse processes. Because its fibres lie behind and to the side of the spine, a two-sided pull extends the neck and a one-sided pull tilts it to that side, the same logic that governs every part of the iliocostalis column.
Keep the three iliocostalis regions in sequence, lumborum, thoracis, and cervicis from below upward, and note that each links one set of ribs to the next level up, so this cervical part carries the chain onto the neck. Its supply by dorsal rami marks it as a true deep back muscle, distinguishing it from anterior neck muscles served by ventral rami.
Frequently asked questions
Where is the Iliocostalis Cervicis located?
The Iliocostalis Cervicis is a muscle of the Back group, located in the Trunk.
What is the origin of the Iliocostalis Cervicis?
Angles of ribs 3–6
What is the insertion of the Iliocostalis Cervicis?
Posterior tubercles of the transverse processes of C4–C6
What movements does the Iliocostalis Cervicis produce?
Bilaterally extends the cervical spine; unilaterally laterally flexes it
What nerve supplies the Iliocostalis Cervicis?
Posterior (dorsal) rami of cervical spinal nerves
Is the Iliocostalis Cervicis free to study in OIANS?
The Iliocostalis Cervicis is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Trunk is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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