Sacrum, and transverse processes of vertebrae.
Spinous processes 2-4 vertebrae superior to origin.
Intervertebral joints of vertebral column.
Extension of vertebral column (bilaterally)
Assists in rotation of vertebral column (unilaterally)
Assists in lateral flexion of spine (unilaterally)
Important to lumbar spine stability because it is a ‘local’ muscle, controlling the fine positioning of adjacent vertebrae.