origin: spinous processes of 3rd to 6th thoracic vertebrae;
insertion: 1st, 2nd, 3rd and sometimes the 4th cervical vertebrae transverse processes on the posterior aspect;
action: acting bilaterally, extends and hyperextends the head and neck; Acting unilaterally flexes and rotates neck to the same side;
nerve supply: posterior rami of the lower cervical spinal nerves;
synergists: Splenius Capitis, Semispinalis capitis, Semispinalis Cervicis, superior portion of Trapezius