Head + Neck Muscles

Question 1

Semispinalis capitis

Answer 1

origin = articular processes of inferior clavicle
transverse process of superior thoracic vertebrae
insertion = occipital bone
action = bilateral: head extension
unilateral: lateral flexion of neck to same side
innervation = accessory nerve (CN XI)

Question 2

Sternocleidomastoid

Answer 2

origin = sternal end of clavicle, manubrium
insertion = mastoid region of skull
action = bilateral: neck flexion
unilateral: contralateral rotation of neck
innervation = accessory nerve (CN XI)

Question 3

Splenius capitis

Answer 3

origin = articular processes of inferior clavicle
transverse process of superior thoracic vertebrae
insertion = occipital bone
action = bilateral: head extension
unilateral: lateral flexion of neck to same side
innervation = cervical spinal nerves

Question 4

Longissimus cervicis

Answer 4

origin = transverse process f superior thoracic vert
insertion = transverse process of middle + upper cerv vert
action = bilateral: head extension
unilateral: lateral flexion of neck to same side
innervation = cervical + thoracic spinal nerves

Question 5

Longissimus thoracis

Answer 5

origin = transverse process of all thoracic + lumber vert
insertion = transverse processes of all thoracic vert
action = bilateral: extension of spine
unilateral: lateral flexion of spine
innervation = thoracic + lumbar spinal nerves

Question 6

Thyrohyoid

Answer 6

origin = thyroid cartilage of larynx
insertion = hyoid bone
action = elevates thyroid, depresses hyoid bone
innervation = hypoglossal nerve

Question 7

Scalenes (anterior/middle/posterior)

Answer 7

origin = transverse processes of C2 - C7
insertion = 1st and 2nd ribs 
action = elevates 1st and 2nd ribs, accessory muscle to breathing
innervation = cervical spinal nerves