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 and flexion to
the same side;
acting bilaterally, extension and hyperextension
of vertebral column; draws ribs down;
nerve supply: posterior rami of the spinal nerves;
synergists: iliocostalis luborum,
Iliocostalis thoracis,
Quadratus Lumborum;
