Origin: the spinous process of the 1st and 2nd lumbar vertebrae, the
thoracic vertebrae 10, 11, 12;
insertion: the spinous process of the thoracic vertebrae 3-8 and
sometimes 9;
action: acting unilaterally, lateral flexion of the spine; acting
bilaterally, extension and hyperextension of the spine;
nerve supply: posterior rami of the spinal nerves;
synergists:
Semispinalis Thoracis ,
Longissimus Thoracis , iliocostalis
thoracis,
i1lioCost8LUMB5[Iliocostalis Lumborum , longissimus thoracis,
Quadratus Lumborum;
