Muscles producing movement of the neck/back

Sternocleidomastoid

O: Sternal head: Manubrium of sternum, Clavicular head: Medial 1/3 of the clavicle
I: Mastoid process of the temporal bone and superior nuchal line of occiput
M: Fusiform, 2 headed muscle
N: Spinal accessory nerve, C2-C3
Unilaterally: Lateral flex the head and neck to the same side, rotate the head and neck to the opposite side
Bilaterally: Flex the neck, assist to elevate the rib cage during inhalation

Scalenes

O: Anterior, middle, posterior transverse processes of C2-C7
I: Anterior and middle - first rib, posterior: second rib 
Fusiform
N: Cervical spinal nerves C3-C8
Unilaterally: Laterally flex the head and neck to the same side, rotate the head and neck to the opposite side
Bilaterally: Elevate the ribs during inhalation, flex the head and neck

Trapezius

O: External occipital protuberance, ligamentum nuchae, spinous processes of C7-T12
I: Lateral 1/3 of clavicle, acromion, and spine of the scapula
Mixed - fibres vary from parallel to multipennate (upper fibres multipennate dominant)
N: Spinal accessory nerves C3-C4
A: Upper fibres bilaterally: Extend the head and neck
Upper fibres unilaterally: Laterally flex the head and neck to the same side, rotate the head and neck to the opposite side, elevate the scapula, upwardly rotate the scapula
Middle fibres: Adduct the scapula, stabilise the scapula
Lower fibres: Depress the scapula, upwardly rotate the scapula

Levator scapulae

O: Transverse process of C1-C4
I: Superior angle and medial border of scapula
N: Cervical C3-C4 and Dorsal scapula C4-C5
Unilaterally: Elevate the scapula, downwardly rotate the scapula, laterally flex the neck, rotate the head and neck to the same side
Bilaterally: Extend the head and neck

Splenius capitis

O: Ligamentum nuchae and spinous processes of C7 to T4
I: Mastoid process of temporal bone and lateral portion of superior nuchal line
N: Posterior rami of spinal nerves C2-C3
Unilaterally: Rotate the head and neck to the same side, laterally flex the head and neck to the same side
Bilaterally: Extend the head and neck

Spinalis

O: Spinous processes of C7-T2 & T11-L3, ligamentum nuchae
I: Spinous processes of cervicals except C1 and upper thoracic vertebrae
N: Posterior rami of lower cervical and upper thoracic nerves
Unilaterally: Laterally flex the vertebral column to the same side
Bilaterally: Extend the vertebral column

Longissimus

O: Transverse process of C4-C6 vertebrae, spinous processes of L1-L5 vertebrae, sacrum, iliac crest
I: Mastoid process of temporal bone, transverse processes of cervical, thoracic, and lumbar vertebrae, ribs 2-12
N: Lateral branches of posterior rami of cervical, thoracic, and lumbar nerves.
Unilaterally: Laterally flexes the vertebral column to the same side
Bilaterally: Extends the vertebral column

Iliocostalis

O: Posterior surface of ribs 1-12, posterolateral aspect of the sacrum, iliac crest
I: Transverse processes of C4-C6, ribs 1-10
N: Lateral branches of posterior rami of lower cervical, thoracic, and lumbar nerves.
Unilaterally: Laterally flexes the vertebral column to the same side 
Bilaterally: Extends the vertebral column 

What are the deep cervical flexor muscles?

Longus coli, longus capitus, rectus capitus, and longus cervicus