Anatomy

Origin

Transverse processes of first lumbar to eleventh thoracic vertebrae. According to some author they are present all along thoracic tract.

Insertion

Transverse processes of next superior vertebra

Nerve

Dorsal primary division of spinal nerves

Actions

They act as stabilizers of the thoracic spine. In theory, their action is to extend thoracic column if acting bilaterally or bend it if activating only in one side. Due to thoracic structure, these movements are very small.