Unit 2 OIAs

Question 1

buccinator

Answer 1

origin: alveolar process of mandible and maxilla
insertion: angle of mouth
action: compresses cheek against molars

Question 2

depressor anguli oris

Answer 2

origin: anterolateral surface of mandibular body
insertion: angle of mouth
action: depresses angle of mouth

Question 3

frontalis

Answer 3

origin: galea aponeurotica
insertion: skin and muscles of forehead
action: raises eyebrows/wrinkles skin of forehead

Question 4

occipitalis

Answer 4

origin: superior nuchal line of occipital bone
insertion: galea aponeurotica
action: tenses scalp, moves outer ear

Question 5

orbicularis oculi

Answer 5

origin: medial margin of bony orbit
insertion: eyelids
action: closes eye

Question 6

orbicularis oris

Answer 6

origin: maxilla and mandible
insertion: skin surrounding mouth
action: closes and purses lips

Question 7

zygomaticus major

Answer 7

origin: zygomatic bone
insertion: angle of mouth
action: raises angle of mouth

Question 8

temporalis

Answer 8

origin: temporal fossa
insertion: coronoid process of mandible
action: closes jaw (elevated mandible)

Question 9

masseter

Answer 9

origin: zygomatic arch
insertion: mandibular angle and ramus
action: closes (elevates) and retracts mandible

Question 10

platysma

Answer 10

origin: skin of lower neck and upper thorax
insertion: lower mandible and skin of lower face
action: tenses skin of neck, depresses mandible

Question 11

risorius

Answer 11

origin: fascia associated with masseter
insertion: angle of mouth
action: draws angle of mouth to side

Question 12

superior rectus

Answer 12

action: elevates eye

Question 13

inferior rectus

Answer 13

action: depresses eye

Question 14

lateral rectus

Answer 14

action: moves eye laterally

Question 15

medial rectus

Answer 15

action: moves eye medially

Question 16

inferior oblique

Answer 16

action: elevates eye and moves eye laterally

Question 17

superior oblique

Answer 17

action: depresses eye and moves eye laterally

Question 18

sternocleidomastoid

Answer 18

origin: 2 heads: manubrium of sternum and clavicle
insertion: mastoid process of temporal bone
action: flexes and rotates cervical vertebral column

Question 19

erector spinae group (spinalis group, longissimus group, iliocostalis group)

Answer 19

action: extends and laterally flexes vertebral column, head, and neck

Question 20

intertransversarii

Answer 20

origin: transverse process of vertebrae
insertion: transverse process of vertebra above
action: laterally flexes vertebral column

Question 21

interspinales

Answer 21

origin: spinous process of vertebrae
insertion: spinous process of vertebra above
action: extends vertebral column

Question 22

rectus abdominis

Answer 22

origin: pubic crest
insertion: xiphoid process and costal cartilages of ribs 5-7
action: compresses abdominopelvic cavity and flexes vertebral column

Question 23

external oblique

Answer 23

origin: lower 8 ribs
insertion: linea alba and anterior iliac crest
action: compresses abdominopelvic cavity, flexes and rotates vertebral column

Question 24

internal oblique

Answer 24

origin: inguinal ligament, iliac crest, and lumbodorsal fascia
insertion: linea alba, pubic crest, and lower ribs
action: compresses abdominopelvic cavity, flexes and rotates vertebral column

Question 25

transversus abdominis

Answer 25

origin: thoracolumbar facia, iliac crest, and cartilages of lower ribs insertion: linea alba and pubic crest action: compresses abdominopelvic cavity

Question 26

external intercostals

Answer 26

origin: inferior border of each rib insertion: superior border of rib below action: elevates ribs

Question 27

internal intercostals

Answer 27

origin: superior border of each rib insertion: inferior border of rib above action: depresses ribs

Question 28

diaphragm

Answer 28

action: elevates lower ribs, expands thoracic cavity for breathing