Iliocostalis muscle is the muscle immediately lateral to the longissimus that is the nearest to the furrow that separates the epaxial muscles from the hypaxial. It lies very deep to the fleshy portion of the serratus posterior muscle. It laterally flexes the vertebral column to the same side.
|Origin||sacrum, iliac crest, thoracolumbar fascia, spinous processes of vertebrae from T11 - L5|
|Artery||intercostal and lumbar arteries|
|Nerve||posterior branch of spinal nerve|
|Actions||Unilaterally: laterally flex the vertebral column to the same side. Bilaterally: Extend the vertebral column.|
|Antagonist||Rectus abdominis muscle|
|Anatomical terms of muscle|
Iliocostalis cervicis (cervicalis ascendens) arises from the angles of the third, fourth, fifth, and sixth ribs, and is inserted into the posterior tubercles of the transverse processes of the fourth, fifth, and sixth cervical vertebrae.
Iliocostalis thoracis (musculus accessorius; iliocostalis thoracis) arises by flattened tendons from the upper borders of the angles of the lower six ribs medial to the tendons of insertion of the iliocostalis lumborum; these become muscular, and are inserted into the upper borders of the angles of the upper six ribs and into the back of the transverse process of the seventh cervical vertebra.
- Anatomy figure: 01:06-06 at Human Anatomy Online, SUNY Downstate Medical Center – "Intrinsic muscles of the back."
- Dissection at ithaca.edu