other back muscles

semispinalis capitus origin

TP of T1-7 & C7

articular processes of C4-6

semispinalis capitus insertion

occipital bone (same as spinalis capitis)

semispinalis capitus action

bilaterally: extension (posterior sagittal rotation)

unilateral: contralateral rotation

semispinalis cervicis origin

TP of top 5-6 thoracic vertebrae

semispinalis cervicis insertion

SP C2-5

semispinalis cervicis action

bilaterally: cervical extension (posterior sagittal rotation)

unilaterally: contralateral rotation

semispinalis thoracis origin

TP of lower 6-10 thoracic vertebrae

semispinalis thoracis insertion

SP C6-T4

semispinalis thoracis action

extension/posterior sagittal rotation

contralateral rotation

multifidus origin

sacral region: posterior sacrum, posterior superior iliac spine, and posterior sacroiliac ligaments

TP of L5-C4

multifidus insertion

spanning 2-4 vertebrae, inserted into SP of vertebrae above

multifidus action

primary stabilizer of L spine

anti-flexion & anti-shear

spine extension

cervical bilateral extension

cervical unilateral contralateral rotation

serratus posterior inferior origin

SP T11-12 and L1-3

serratus posterior inferior insertion

inferolateral ribs T9-12

serratus posterior inferior action

unclear action

rotatores origin

TP of vertebrae

rotatores insertion

lamina of vertebra above

rotatores action

bilateral extension

unilateral contralateral rotation

interspinales

origin/insertion: between SP in pairs

action: cervical extension

intertransversarii

origin/insertion: between TPs

action: cervical lateral flexion

splenius capitis

origin: ligamentum nuchae, SP of C7 T1-6

insertion: mastoid process and occipital bone

actions:

ipsilateral rotation and cervical extension

innervation: greater occipital C2

splenius cervicis

origin: ligamentum nuchae, SP C7 T1-6

insertion: posterior tubercles of TP C1-3

actions: ipsilateral rotation, extension

innervations: least/third occipital nerve C3