Neck Muscles

Question 1

Sternocleidomastoid

Answer 1

O: Sternal head: anterior surface of manubrium
Clavicular head: medial 1/3 of clavicle
I: Mastoid process (via strong tendon)

Action: Cervical flexion, side flexion and rotation

Question 2

Splenius

Answer 2

Splenius capitis and cervicis
O: Ligamentum nuchae,
SP of C7-T6
I: Nuchal line, 
Mastoid process
TPs of C1-C3

Action: Cervical rotation and side flexion, ?cervical extension

Question 3

Levator scapulae

Answer 3

O: Posterior tubercle of C1-4 TPs
I: Medial border of scapula (between superior angle and the root of the spine).
Action: Cervical extension and side flexion

Question 4

Trapezius

Answer 4

O: Medial 1/3 of superior nuchal line
External occipital protruberance
Nuchal ligament
SPs of C7 - T12
I: lateral 1/3 of clavicle
acromion
spine of scapula

Action: Cervical extension and side flexion

Question 5

Erector spinae

Answer 5

O: Sacrum, iliac crest, SPs and TPs of vertebrae
Ribs

I: Ribs, SPs and TPs of vertebrae, occipital bone

Action: Cervical extension

Question 6

Scalenes

Answer 6

O:
Scalenus Anterior: TPs of C3-C6
Scalenus Medius: TPs of C2-C7
Scalenus Posterior: TPs of C5-C7

I:
Scalenus Anterior: First rib (Scalene tubercle)
Scalenus Medius: First rib (Superior surface behind subclavian artery)
Scalenus Posterior: Second rib (Lateral surface)

Action: Cervical side flexion