Deep Muscles of the Back

iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament

erector spinae origin

angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull

erector spinae insertion

segmentally innervated by dorsal primary rami of spinal nerves C1-S5

erector spinae nerve

extends and laterally bends the trunk, neck and head

erector spinae action

iliac crest and sacrum

iliocostalis origin

angles of the ribs

iliocostalis insertion

dorsal primary rami of spinal nerves C4-S5

iliocostalis nerve

extends and laterally bends the trunk and neck

iliocostalis action

upper border of spinous process

interspinales origin

lower border of spinous process above

interspinales insertion

dorsal primary rami of spinal nerves C1-L5

interspinales nerve

extend trunk and neck

interspinales action

upper border of transverse process

intertransversarii origin

lower border of transverse process above

intertransversarii insertion

dorsal primary rami of spinal nerves C1-L5

intertransversarii nerve

laterally bend trunk and neck

intertransversarii action

transverse process at inferior vertebral levels

longissimus origin

transverse process at superior vertebral levels and mastoid process

longissimus insertion

dorsal primary rami of spinal nerves C1-S1

longissimus nerve

extends and laterally bends the trunk, neck and head

longissimus action

sacrum, transverse processes of C3-L5

multifidus origin

spinous processes 2-4 vertebral levels superior to their origin

multifidus insertion

dorsal primary rami of spinal nerves C1-L5

multifidus nerve

extend and laterally bend trunk and neck, rotate to opposite side

multifidus action

spinous process of the axis

obliquus capitis inferior origin

transverse process of atlas

obliquus capitis inferior insertion

suboccipital nerve (DPR of C1)

obliquus capitis inferior nerve

rotates the head to the same side

obliquus capitis inferior action

transverse process of atlas

obliquus capitis superior origin

occipital bone above inferior nuchal line

obliquus capitis superior insertion

suboccipital nerve (DPR of C1)

obliquus capitis superior nerve

extends the head, rotates the head to the same side

obliquus capitis superior action

spinous process of axis

rectus capitis posterior major origin

inferior nuchal line

rectus capitis posterior major insertion

suboccipital nerve (DPR of C1)

rectus capitis posterior major nerve

extends the head, rotate to same side

rectus capitis posterior major action

posterior tubercle of atlas

rectus capitis posterior minor origin

nferior nuchal line medially

rectus capitis posterior minor insertion

suboccipital nerve (DPR of C1)

rectus capitis posterior minor nerve

extends the head

rectus capitis posterior minor action

transverse processes

rotatores origin

long rotatores: spines 2 vertebrae above origin; short rotatores: spines 1 vertebrae above origin

rotatores insertion

dorsal primary rami of spinal nerves C1-L5

rotatores nerve

rotates the vertebral column to the opposite side

rotatores action

transverse processes of C7-T12

semispinalis origin

capitis: back of skull between nuchal lines; cervicis & thoracis: spines 4-6 vertebrae above origin

semispinalis insertion

dorsal primary rami of spinal nerves C1-T12

semispinalis nerve

extends the trunk and laterally bends the trunk, rotates the trunk to the opposite side

semispinalis action

thoracolumbar fascia, spines of vertebrae T11- T12 and L1-L2

serratus posterior inferior origin

ribs 9-12, lateral to the angles

serratus posterior inferior insertion

branches of the ventral primary rami of spinal nerves T9-T12

serratus posterior inferior nerve

pulls down lower ribs

serratus posterior inferior action

ligamentum nuchae, spines of vertebrae C7 and T1-T3

serratus posterior superior origin

ribs 1-4, lateral to the angles

serratus posterior superior insertion

branches of the ventral primary rami of spinal nerves T1-T4

serratus posterior superior nerve

elevates the upper ribs

serratus posterior superior action

spinous processes at inferior vertebral levels

spinalis origin

spinous processes at superior vertebral levels and base of the skull

spinalis insertion

dorsal primary rami of spinal nerves C2-L3

spinalis nerve

extends and laterally bends trunk and neck

spinalis action

ligamentum nuchae and spines C7-T6

splenius origin

capitis: mastoid process & superior nuchal line laterally; cervicis: posterior tubercles of C1-C3 vertebrae

splenius insertion

dorsal primary rami of spinal nerves C2-C6

splenius nerve

extends and laterally bends neck and head; rotates head to same side

splenius action

ligamentum nuchae and spines of C7-T6 vertebrae

splenius capitis origin

mastoid process and lateral end of the superior nuchal line

splenius capitis insertion

dorsal primary rami of spinal nerves C2-C6

splenius capitis nerve

extends and laterally bends the neck and head, rotates head to the same side

splenius capitis action

ligamentum nuchae and spines of C7-T6 vertebrae

splenius cervicis origin

posterior tubercles of the transverse processes of C1-C3 vertebrae

splenius cervicis insertion

dorsal primary rami of spinal nerves C2-C6

splenius cervicis nerve

extends and laterally bends neck and head, rotates head to the same side

splenius cervicis action