Origin/Insertion of Muscles - Erector Spinae (Iliocostalis Group - Cervicis, Thoracis, Lumborum)

Iliocostalis Group - Cervicis, Thoracis, Lumborum
Origin: Superior borders of ribs and Iliac Crest
Insertion: Transverse processes of Cervical vertebrae and Inferior surfaces of ribs
Action: Extends vertebral column or moves laterally to that side; moves ribs

Iliac Crest

Rib Cage

Transverse Process

Origin/Insertion of Muscles - Erector Spinae (Longissimus Group - Capitis, Cervicis, Thoracis)

Longissimus Group - Capitis, Cervicis, Thoracis

Origin: Processes of the lower cervical, thoracic and upper lumber vertebrae
Insertion: Mastoid process of the temporal bone, transverse process of cervical vertebrae and inferior surface of ribs
Action: Two sides act together to extend vertebral column; either alone rotates and laterally flexes head or vertebral column to that side

Longissimus Muscle Group

Mastoid Process of Temporal bone

Transverse Processes