Muscles of the vertebral column: Head movements and trunk extension

innervation of sternocleidomastoid

Accessory nerve (XI)

innervation of scalenes muscles

Anterior rami of cervical spinal nerves

innervation of splenius capitis

Posterior rami cervical spinal nerves

innervation of quadratus lumborum

anterior rami of lumbar spinal nerves

Quadratus lumborum: Action

each flexes vertebral column laterally

Semispinalis capitis: Action

extend vertebral column and head

Quadratus lumborum: Origin

iliac crest

Quadratus lumborum: Insertion

inferior border of last rib (12th) & transverse processes of lumbar vertebrae

Erector spinae: Action

maintain posture, extends, and bends the vertebral column laterally; longissimus also extends and rotates the head

Sternocleidomastoid : Origin

manubrium of sternum and medial portion of clavicle

Semispinalis capitis: Insertion

occipital bone and spinous processes of cervical vertebrae and T1-T4

innervation of semispinalis

posterior rami of cervical and thoracic spinal nerves

innervation of erector spinae

posterior rami of cervical to lumbar spinal nerves

Splenius capitis: Origin

spinous processes of C7-T6

Semispinalis capitis: Origin

transverse processes of C7-T12

Scalenes (anterior, middle, posterior): Origin

transverse processes of cervical vertebrae

Erector spine: Origin

various sites; cervical, thoracic, and lumbar vertebrae, ribs, and sacrum

Erector spinae: Insertion

various sites; occipital bone, mastoid process, cervical and thoracic vertebrae