intrinsic back muscles

Serratus posterior superior — Serratus (superficial intrinsic) (blue)

Origin: Upper thoracic vertebrae;

Insertion: Upper ribs;

Action: Elevation of ribs;

Innervation: Anterior rami

Serratus posterior inferior — Serratus (superficial intrinsic) (green)

Origin: Lower thoracic vertebrae;

Insertion: Lower ribs;

Action: Depression of ribs;

Innervation: Anterior rami

Splenius capitis — Splenius (superficial intrinsic) (blue)

Origin: Cervical vertebrae;

Insertion: Base of skull;

Action: Extension, lateral flexion, rotation of head and neck;

Innervation: Posterior rami

Splenius cervicis — Splenius (superficial intrinsic) (green) 

Origin: Upper thoracic vertebrae;

Insertion: Cervical vertebrae;

Action: Extension, lateral flexion, rotation of head and neck;

Innervation: Posterior rami

Iliocostalis — Erector spinae (intermedite intrinsic) (purple)

Origin: Iliac crest, sacrum;

Insertion: Ribs;

Action: Extension, lateral flexion of spine; Innervation:

Posterior rami

Longissimus — Erector spinae (intermediate intrinsic) (blue)

Origin: Spinous processes;

Insertion: Transverse processes;

Action: Extension, lateral flexion of spine;

Innervation: Posterior rami

Spinalis — Erector spinae (intermediate intrinsic) (green)

Origin: Transverse processes;

Insertion: Spinous processes;

Action: Extension, lateral flexion of spine;

Innervation: Posterior rami

Semispinalis — Transversospinalis (Deep intrinsic) (purple)

Origin: Transverse processes;

Insertion: Spinous processes;

Action: Extension, rotation, stabilization of spine;

Innervation: Posterior rami

4-6 segments long 

Multifidus — Transversospinalis (Deep intrinsic) (green)

Origin: Spinous processes;

Insertion: Ribs;

Action: Extension, rotation, stabilization, proprioception;

Innervation: Posterior rami

2-4 segments long

Rotatores — Transversospinalis (Deep intrinsic) (blue)

Origin: Transverse processes;

Insertion: Transverse processes;

Action: Extension, rotation, stabilization of spine;

Innervation: Posterior rami

1-2 segments long

Interspinales — Segmentals (Deep intrinsic) (purple) 

Origin: Spinous processes;

Insertion: Spinous processes;

Action: Extension, stabilization of spine;

Innervation: Posterior rami

Intertransversarii — Segmentals (Deep intrinsic) (blue)

Origin: Transverse processes;

Insertion: Transverse processes;

Action: Lateral flexion, stabilization of spine;

Innervation: Anterior rami

Levatores costarum — Segmentals (Deep intrinsic) (green)

Origin: Transverse processes;

Insertion: Ribs;

Action: Elevation of ribs;

Innervation: Posterior rami

posterior rami