Iliocostalis Cervicis
Back
This is one of those quiet posture muscles that helps keep your neck upright while you drive, study, or look forward for long periods.
Function
Bilaterally extends the cervical spine and helps maintain upright posture. Unilaterally laterally flexes the neck to the same side and assists with cervical stabilization.
Origin
Angles of ribs 3–6.
Insertion
Posterior tubercles of the transverse processes of C4–C6 vertebrae. Some sources may include C4–C7.
Innervation
Dorsal rami of cervical spinal nerves, with possible contribution from upper thoracic levels.