origin: transverse process of the first to fifth thoracic vertebrae;
insertion: transverse processes of the 2nd to 6th cervical vertebrae and
 
 
 
 
 
 
sometimes to the atals transverse process;
action: acting unilaterally, laterally flexes the neck; acting
 
 
 
 
bilaterally, extension and hypertension of the neck;
nerve supply: posterior rai of the spinal nerves;
synergists:  
 
Semispinalis capitis ,  
 
[Semispinalis Cervicis ,
 
 
 
 
 
 
 
Iliocostalis Cervicis ,  
Longissimus Capitis ,  
Spinalis Cervicis ,
 
 
 
 
 
 
and the deep posterior spinal group;