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| Muscle | Origin | Insertion | Action | Nerve |
| Erector Spinae Group |
| iliocostalis | lumborum: medial iliac crest & sacrum
thoracis: angle of ribs 7-12
cervicis: angle of ribs 3-6 | lumborum: angle of ribs 7-12
thoracis: angle of ribs 1-6
cervicis: TPs of C3-C6 | bilateral: extension of the spine (maintenance of erect posture); unilateral: lateral flexion & rotation to same side of the spine & head; opposite muscles contract eccentrically for stabilization | dorsal rami of spinal nerves |
| longissimus | thoracis: iliac crest, posterior sacrum, TPs L1-L5
cervicis: TPs of T1-T5
capitis: TPs & articular processes of C5-C7 & TPs of T1-T4 | thoracis: TPs of T1-12 & ribs 4-12 (medial to tubercle)
cervicis: TPs & posterior tubercles of C2-C6
capitis: temporal bone (mastoid process) | bilateral: extension of the spine & head (maintenance of erect posture); unilateral: lateral flexion & rotation to same side of the spine & head; opposite muscles contract eccentrically for stabilization | dorsal rami of spinal nerves |
| spinalis | thoracis: SPs T11-L2
cervicis: SP of C7 & inferior nuchal ligament
capitis: TPs of C7-T6 & articular process of C4-C6 (medial part of semispinalis) | thoracis: SPs of T4-T8
cervicis: SP of C2
capitis: occipital bone (considered to be the medial part of semispinalis) | bilateral: extension of the spine & head (maintenance of erect posture); unilateral: lateral flexion & rotation to same side of the spine & head; opposite muscles contract eccentrically for stabilization | dorsal rami of spinal nerves |
| Transversospinalis Group |
| semispinalis | thoracis: TPs of T6-T10
cervicis: TPs of T1-T5
capitis: TPs of C7-T6 & articular process of C4-C6 | thoracis: SPs of C6-T4
cervicis: SPs of C2-C5
capitis: occipital bone (between superior & inferior nuchal lines) | bilateral: extension of head & neck; controls lateral flexion to side opposite contraction (eccentric for stability); maintains head posture | spinal nerve (dorsal rami) |
| multifidus | lumbar: mamillary processes of L1-L5 (not TPs)
thoracic: TP of T1-T12
cervical: articular processes of C4-C7 (not TPs) | SPs of all vertebrae extending from L5 - C2, 3-4 segments above the origin | bilateral: extension of vertebral column (trunk & neck); unilateral: rotate vertebral bodies (column) to opposite side; control lateral flexion to side opposite contraction (eccentric for stability) | spinal nerve (dorsal rami) |
| rotatores | transverse processes of C3-L5 (most developed in thoracic spine) | spinous process (base) & lamina 1-2 segments above origin | rotation to opposite side, bilateral extension; stabilize vertebra & are involved as organs of proprioception (position sense of the spine due to the large number of sensory nerve fibers in these tiny muscles) | spinal nerve (dorsal rami) |
| Other deep group muscles |
| quadratus lumborum | 12th rib (inferior border) & TPs of L1-L4 | posterior iliac crest & iliolumbar ligament | elevation of pelvis; lateral flexion of trunk; depression of 12th rib | lumbar plexus (T12-L3) |
| interspinalis | SP of vertebrae | SP of vertebrae above | extension of neck & trunk | dorsal rami of spinal nerves |
| intertransversarii | TP of vertebrae | TP of vertebrae above | lateral flexion of neck & trunk | dorsal rami of spinal nerves |
| levator costarum | TPs C7-T11 (posterior lateral tip) | ribs 1-12 (below the TP) | elevation of ribs (inspiration) | dorsal rami of spinal nerves |
Vertebral Column