Iliocostalis Lumborum Muscle
The iliocostalis lumborum muscle lies lateral to the longissiumus muscle group and deep to the serratus posterior muscle. It s a part of the erector spinae muscles that function to straighten and laterally flex the vertebrae column.
Origin: medial and lateral sacral crests; medial iliac crest.
Insertion: angles of ribs 6 or 7 – 12.
Bilaterally (both) muscle contraction:
Extend the vertebral column.
Unilateral (one) muscle contraction:
Laterally flex the vertebral column
to the same side.
Muscle Nerve Supply
Dorsal primary rami of thoracic and lumbar spinal nerves (T7 to L3).