Longissimus Thoracis
origin: the common broad thich tendon with Iliocostalis Lumborum, fibers from the transverse and mamillary processes of the lumbar vertebrae and lumbrosacral aponeurosis; insertion: the tips of transverse process of all thoracic vertebrae and the lower 9 or 10 ribs between the tubercles and angles; action: acting unilaterally, extension of vertebral column … Read more