Cervical spine innervation and action

Question 1

Upper trapezius

Answer 1

Innervation: Motor–spinal part of the accessory nerve
Sensory–anterior rami of C3-C4
Action: Powerful elevator of scapula
Rotator of scapula during abduction of humerus
above horizontal

           Middle fibers retract scapula
           Lower fibers depress scapula

Question 2

Deep cervical multifidus

Answer 2

Innervation: Medial branch of dorsal rami
Action: Stabilizes vertebrae in local movement of
vertebral column
Bilaterally extends vertebral column
Unilaterally produces contralateral rotation

Question 3

Superficial Cervical

Answer 3

Innervation: segmental
Action: extend cervical spine and head, rotate cervical
spine

Question 4

Splenis capitus

Answer 4

Innervation: Posterior rami of middle cervical nerves
Action: Bilaterally neck extension
Unilaterally Ipsilateral rotation

Question 5

Splenis cervicus

Answer 5

Innervation: Posterior rami of lower cervical nerves
Action: Bilaterally neck extension
Unilaterally ipsilateral rotation

Question 6

Erector spinal cervicus:
Iliocostalis cervicis–lateral column
Longissimus cervicis–intermediate column
Spinalis cervicis–medial column

Spinalis capitis

Answer 6

Innervation: Posterior rami of spinal nerves
Action: Primary extensors of vertebral column and head
Bilaterally extend the vertebral column/head
Unilaterally lateral flexion of vertebral
column/head

Question 7

Semispinalis cervicis

Answer 7

Innervation: posterior rami of spinal nerves
Action: Bilaterally extends vertebral column
Unilaterally contralateral rotation

Question 8

Semispinalis capitis

Answer 8

Innervation: posterior rami of spinal nerves
Action: Bilaterally pulls head posteriorly
Unilaterally pulls head posteriorly and turns it