Muscles of the Axial Skeleton

Question 1

Epicranius Frontalis

Answer 1

Action: Raises eyebrows
Origin: Aponeurosis
Insertion: Skin eyebrows
Innervation: Facial
(forehead, above eyes)

Question 2

Epicranius Occipitalis

Answer 2

Action: Pulls scalp posterior
Origin: Occipital bone
Insertion: Aponeurosis
Innervation: Facial
(back of head, two strips)

Question 3

Orbicularis oculi

Answer 3

Action: Close eyelids 
Origin: Frontal and maxillary bones
Insertion: Skin of eyelid
Innervation: Facial
(surrounding each eye)

Question 4

Risorius

Answer 4

Action: Draws corner of lip laterally
Origin: Fascia of Masseter
Insertion: Skin at angle of mouth
Innervation: Facial
(on cheek, connecting with orbicularis oris)

Question 5

Orbicularis oris

Answer 5

Action: Close lips
Origin: Maxilla and mandible
Insertion: Skin of mouth
Innervation: Facial
(surrounding lips in a circle around mouth)

Question 6

Zygomaticus major and minor

Answer 6

Action: elevates corners of mouth
Origin: zygomatic bone
Insertion: skin and muscles at corner of mouth
Innervation: facial

Question 7

Buccinator

Answer 7

Action: compress cheek and draws corner of mouth laterally
Origin: molar region of mandible and maxillae
Insertion: orbicularis oris
Innervation: facial
(between zygomaticus major and risorius)

Question 8

Depressor labii inferioris

Answer 8

Action: draws lower lip inferiorly
Origin: body of mandible lateral to midline
Insertion: skin and muscle of lower lip
Innervation: facial

Question 9

Levator labii superioris

Answer 9

Action: elevates upper lip
Origin: zygomatic bone and maxilla
Insertion: skin and muscle of upper lip
Innervation: facial

Question 10

Depressor anguli oris

Answer 10

Action: draws corners of mouth down and lateral
Origin: body of mandible below incisors
Insertion: skin and muscle at angle of mouth
Innervation: facial
(adjacent to depressor labii inferioris, on the side farther away from chin)

Question 11

Mentalis

Answer 11

Action: protrudes lower lip, and wrinkles chin
Origin: anterior body of mandible
Insertion: skin of chin
Innervation: facial
(chin)

Question 12

Masseter

Answer 12

Action: elevate mandible
Origin: zygomatic arch and maxilla
Insertion: angle and ramus of mandible
Innervation: trigeminal

Question 13

Temporalis

Answer 13

Action: elevate and retract mandible
Origin: temporal fossa
Insertion: coronoid process of mandible
Innervation: trigeminal
(big muscle on side of head)

Question 14

Platysma

Answer 14

Action: depress mandible, tense skin of neck
Origin: fascia of chest (fascia over deltoid and pectoralis major)
Insertion: lower margin of mandible, skin, muscle at corner of mouth
Innervation: facial

Question 15

Sternocleidomastoid

Answer 15

Action: flex neck and rotate head toward opposite side
Origin: manubrium and clavicle
Insertion: mastoid process of temporal bone
Innervation: accessory
(right behind ear and down)

Question 16

Scalene (anterior, middle, and posterior)

Answer 16

Action: flex and rotate neck, elevate ribs
Origin: transverse process of cervical vertebrae
Insertion: ribs 1 and 2
Innervation: cervical and brachial plexus (C3-6)

Question 17

Diagastrics anterior

Answer 17

Action: elevate hyoid, depress mandible as in open mouth
Origin: lower inner margin of mandible
Insertion: body of hyoid bone
Innervation: trigeminal

Question 18

Diagastrics posterior

Answer 18

Action: elevate hyoid, depress mandible as in open mouth
Origin: mastoid process
Insertion: body of hyoid bone
Innervation: facial

Question 19

Stylohyoid

Answer 19

Action: elevates and retracts hyoid
Origin: styloid process of temporal bone
Insertion: hyoid bone
Innervation: facial

Question 20

Mylohyoid

Answer 20

Action: elevate hyoid bone during swallowing
Origin: inner surface of mandible
Insertion: hyoid bone
Innervation: trigeminal

Question 21

Sternohyoid

Answer 21

Action: depresses larynx and hyoid bone
Origin: manubrium and clavicle
Insertion: hyoid bone
Innervation: C1-C3

Question 22

Levator scapulae

Answer 22

Action: elevate and adducts scapula
Origin: transverse process of C1-C4
Insertion: scapula medial border above spine
Innervation: C3-4, dorsal scapula
(from top of cervical vertebrae to medial border of scapula)

Question 23

Pectoralis minor

Answer 23

Action: elevates upper ribs, moves scapula forward
Origin: ribs 3-5
Insertion: coracoid process
Innervation: pectoral

Question 24

Serratus anterior

Answer 24

Action: move scapula forward, rotate scapula laterally
Origin: lateral aspect of ribs 1-8
Insertion: medial border of scapula
Innervation: long thoracic

Question 25

External intercostals

Answer 25

Action: elevate rib cage, aid in inspiration Origin: inferior border of rib above Insertion: superior border of rib below Innervation: intercostal

Question 26

Internal intercostals

Answer 26

Action: depress rib cage, aid in expiration Origin: superior border of rib below Insertion: inferior border of rib above Innervation: intercostal

Question 27

Diaphragm

Answer 27

Action: prime mover of inspiration, flattens when contracts, lengthens thoracic cavity Origin: Insertion: Innervation: phrenic

Question 28

Rectus abdominis

Answer 28

``` Action: flex and rotate vertebral column Origin: pubic crest and symphysis Insertion: xiphoid process and cartilages of ribs 5-7 Innervation: intercostal (abs) ```

Question 29

External oblique

Answer 29

Action: trunk rotation and lateral flexion; compresses abdomen; depresses ribs Origin: anterior surface of ribs 5-12 Insertion: pubic crest, pubic tubercle, iliac crest, and linea alba Innervation: intercostal, iliohypogastric (just above hip)

Question 30

Internal oblique

Answer 30

Action: trunk rotation and lateral flexion; compresses abdomen; depresses ribs Origin: iliac crest, inguinal ligament, lumbar fascia Insertion: linea alba, ribs 9-12 (cartilage), pubic crest Innervation: intercostal; iliohypogastric; ilioinguinal

Question 31

Transversus abdominis

Answer 31

Action: compresses abdomen Origin: iliac crest, cartilages of ribs 6-12, inguinal ligament Insertion: pubic crest, linea alba Innervation: intercostal; iliohypogastric, ilioinguinal

Question 32

Trapezius

Answer 32

Action: extend neck; raise, rotate, and adduct scapula Origin: occipital bone, spine of C7, and all thoracic vertebrae Insertion: acromion and spine of scapula Innervation: accessory (between neck and shoulder)

Question 33

Latissimus dorsi

Answer 33

Action: extend, adduct, medially rotate arm Origin: T6-L5 spinous processes, ribs 8-12, iliac crest Insertion: intertubercular groove; humerus Innervation: thoracodorsal (lats)

Question 34

Errector Spinae: longissimus, iliocostalis, spinalis

Answer 34

Action: as a pair-extend neck and vertebral column; single-bend vertebrae laterally Origin: transverse process of C7-T12 Insertion: occipital bone and spinous process of cervical vertebrae Innervation: (spinalis in center of vertebral column, then longissimus next and between the two other errector spinae, and iliocostalis is farthest laterally)