Iliac crest and Iliolumbar fascia.
Upper 4 lumbar vertebrae and lower margin of 12th rib.
Intervertebral joints of lumbar vertebrae.
Unilateral concentric contraction: lateral flexion of lumbar spine.
Unilateral isometric contraction: prevents lateral flexion of lumbar spine (e.g. when carrying a heavy suitcase in one hand).
Bilateral eccentric contraction: assists in preventing hyperflexion of lumbar spine.