Muscles of the Head, Neck, and Trunk

Question 1

Scalenes

origin, insertion, action

Answer 1

origin: transverse process of cervical vertebrae
insertion: ribs 1 and 2
action: flexes neck

Question 2

Sternocleidomastoid

origin, insertion, action

Answer 2

origin: sternum
insertion: mastoid process of temporal
action: abducts head

Question 3

Temporalis

origin, insertion, action

Answer 3

origin: temporal fossa
insertion: coronoid process
action: closes mandible

Question 4

Masseter

origin, insertion, action

Answer 4

origin: zygomatic arch
insertion: angle of mandible
action: closes mandible

Question 5

Orbicularis oris

origin, insertion, action

Answer 5

origin: fascia of facial muscles near mouth
insertion: skin of lips
action: closes lips

Question 6

Orbicularis oculi

origin, insertion, action

Answer 6

origin: frontal
insertion: skin of eyelid
action: closes eyelid

Question 7

Serratus anterior

origin, insertion, action

Answer 7

origin: ribs 1-8
insertion: vertebral border and inferior angle of scapula
action: abducts scapula

Question 8

External intercostals

origin, insertion, action

Answer 8

origin: inferior border of a rib
insertion: superior border of rib below
action: elevates ribs away from midline

Question 9

Internal intercostals

Answer 9

origin: inferior border of a rib
insertion: superior border of rib below
action: collapses rib toward the midline

Question 10

Diaphragm

Answer 10

origin: xiphoid process
insertion: central tendon
action: inspiration

Question 11

External abdominal oblique

Answer 11

origin: ribs 5-12
insertion: linea alba
action: compresses abdominal wall

Question 12

Rhomboideus major

Answer 12

origin: spines of T2-5
insertion: lower one-third of vertebral border of scapula
action: adducts scapula