The erector spinae is the largest muscle mass of the back. It lies in the intermediate layer of intrinsic back muscles.
It is divided into three longitudinal columns:
Acting unilaterally, the three muscle groups act to laterally flex the ipsilateral spine. Bilateral contraction as a unit flexes the spine.
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.