muslces of the back (deep layer)

Semispinalis capitis origin,

Transverse and articular processes of C4–T7

Semispinalis capitis insertion,

Between superior and inferior nuchal lines

Semispinalis capitis action,

Together: neck extension; independently: lateral flexion to same side (shared action entry for semispinalis muscles)

Semispinalis capitis innervation,

Dorsal rami of spinal nerves

Semispinalis cervicis origin,

Transverse processes of T1–T6

Semispinalis cervicis insertion,

Spinous processes of C2–C5

Semispinalis cervicis action,

Together: neck extension; independently: lateral flexion to same side (shared action entry for semispinalis muscles)

Semispinalis cervicis innervation,

Dorsal rami of spinal nerves

Semispinalis thoracis origin,

Transverse processes of T6–T12

Semispinalis thoracis insertion,

Spinous processes of C6–T4

Semispinalis thoracis action,

Together: neck extension; independently: lateral flexion to same side (shared action entry for semispinalis muscles)

Semispinalis thoracis innervation,

Dorsal rami of spinal nerves

Multifidus origin,

1. Posterior sacrum; 2. PSIS; 3. Mammillary processes of L1–L5; 4. Transverse and articular processes of T1–T4, C4–C7; 5. Facet joint capsules

Multifidus insertion,

Spinous process of vertebra 2–4 levels higher

Multifidus action,

1. Back extension; 2. Vertebral column rotation to opposite side; 3. Lateral flexion to same side

Multifidus innervation,

Dorsal rami of spinal nerves

Rotatores origin,

Transverse processes of thoracic vertebrae

Rotatores insertion,

Spinous process of vertebra one or two vertebrae superiorly

Rotatores action,

1. Back extension; 2. Vertebral column rotation to opposite side

Rotatores innervation,

Dorsal rami of spinal nerves