origin: superior borders of the angles of the 3rd to 6th ribs;
insertion: the posterior tubercles of the transverse processes of the 4th, 5th, and 6th cervical vertebrae;
action: acting bilaterally, extends and hyperextends the vertebral column;
nerve supply: posterior rami of the spinal nerve, C6, C7, C8 ;
synergists: splenius cervicis, Semispinalis Cervicis Longissimus Cervicis