intrinsic back actions and innervations

erect

spinotransversalis (splenius capitus and splenius cervicis)

innervation: posterior rami of spinal nerves
action: alone: laterally flex neck and rotate head to side of active muscles. together: extend head and neck

semispinalis (transversospinalis)

innvervation: posterior rami of spinal nerve

action: Extends head and throacic and cervical regions of vertebral column and rotates them contralaterally

multifidus (transversospinalis)

innveration: posterior rami of spinal nerves
action: Unilateral contraction rotates to bilateral side, stabilizes vertebrae during local movements of vetebral column

rotatores (transversospinalis)

innervation: posterior rami of spinal nerves

action: organs of proprioception, stabalize vertebrae, assit with local extension and rotary movements of veterbal column

interspinalis (segmental)

innvervation: posterior rami of spinal nerves
action: extension and rotation of vertebral column

intertransversi

innvervation: posterior and anterior rami of spinal nerves

action: lateral flexion of vetebral column/ bilaterally stabilizes vetebral column

suboccipital muscles (obliquus capitis superior, inferior and rectus capitus posterior major, minor)

innervation: posteior ramus of C1: Suboccipital nerve

action: extend the head on C1, rotate head and C1 on C2 vertebrae