| Term | Definition |
| Splenius Capitus IA | Ligamentum nuchae, spinous process of C7 to T4 |
| Splenius Capitus SA | Mastoid process, lateral superior nuchal line |
| Splenius Capitus N | Posterior primary rami |
| Splenius Capitus Action | Bilateral extension of the head and neck. Unilateral Ipsilateral rotation of head and neck |
| Splenius Cervicis IA | Ligamentum nuchae, spinous process of C7 to T4 |
| Splenius Cervicis SA | Transverse processes of C1-C3 |
| Splenius Cervicis N | Posterior primary rami |
| Splenius Cervicis Action | Bilateral extension of the head and neck. Unilateral Ipsilateral rotation and lateral flexion of the neck |
| Iliocostalis IA | Iliac crest, sacrum and spinous processes of the inferior lumbar vertebrae |
| Iliocostalis SA | Angles of ribs and transverse processes of cervical vertebrae |
| Iliocostalis N | Posterior primary rami |
| Iliocostalis Action | Bilateral Extension of the vertebral column. Unilateral Ipsilateral rotation and lateral flexion of the vertebral column |
| Longissimus IA | Iliac crest, sacrum and spinous processes of the inferior lumbar vertebrae |
| Longissimus SA | Ribs and transverse processes of thoracic/cervical vertebrae |
| Longissimus Capitus SA | Mastoid process of the temporal bone |
| Longissimus N | Posterior primary rami |
| Longissimus Action | Bilateral extension of the vertebral column and head. Unilateral Ipsilateral rotation and lateral flexion of the vertebral column and head |
| Spinalis IA | Iliac crest, sacrum and spinous processes of the inferior lumbar vertebrae |
| Spinalis SA | Spinous processes of thoracic vertebrae and fuse with fibers of semispinalis capitis |
| Spinalis N | Posterior primary rami |
| Spinalis Action | Bilateral extension of the vertebral column. Unilateral Ipsilateral rotation and lateral flexion of the vertebral column |