Muscles of the face

Question 1

Sternocleidomastoid

Answer 1

Origin: Manubrium of sternum; medial 1/3 of clavicle

Insertion: Mastoid process; lateral 1/2 of superior nuchal line

Action:

• Unilateral action tilts head slightly upward and toward the opposite side; rotates head left/right.
• Bilateral action draws head straight forward and down.
• Aids in deep breathing when head is fixed

Question 2

Longissimus capitis

Answer 2

Origin: Transverse processes of T1-T5; articular processes of C4 or C5-C7

Insertion: Posterior portion of the mastoid process of the temporal bone

Action:

• Bilateral action extends and hyperextends the head
• Unilateral action laterally flexes and rotates the head to the same side

Question 3

Semispinalis capitis

Answer 3

Origin: Articular processes of vertebrae C4-C7; transverse processes of T1-T6

Insertion: Occipital bone between nuchal lines; spinous processes of vertebrae C2-C5

Action: Extend and contralaterally rotate head

Question 4

Splenius capitis

Answer 4

Origin: Inferior occipital protuberance; medial 1/3 of superior nuchal line; nuchal ligament; spinous processes of vertebrae C7-T3 or T4

Insertion: Mastoid process and occipital bone just inferior to superior nuchal line; cervical vertebrae C1-C2 or C3

Action:

• Unilateral action produces ipsilateral flexion and slight rotation of head
• Bilateral action extends head

Question 5

Omohyoid

Answer 5

Origin: Superior border of scapula

Insertion: Hyoid bone

Action: Depresses hyoid after it has been elevated

Question 6

Sternohyoid

Answer 6

Origin: Manubrium of sternum; medial end of clavicle

Insertion: Hyoid bone

Action: Depresses hyoid after it has been elevated

Question 7

Sternothyroid

Answer 7

Origin: Manubrium of sternum; costal cartilage 1

Insertion: Thyroid cartilage of larynx

Action: Depresses larynx after it has been elevated in swallowing and vocalization; aids in singing low notes

Question 8

Thyrohyoid

Answer 8

Origin: Thyroid cartilage of larynx

Insertion: Hyoid bone

Action: Depresses hyoid; with hyoid fixed, elevates larynx

Question 9

Stylohyoid

Answer 9

**Origin: ** Styloid process of temporal bone

Insertion: Hyoid bone

Action: Elevates and retracts hyoid, elongating floor of mouth

Question 10

Geniohyoid

Answer 10

Origin: Inferior mental spine of mandible

Insertion: Hyoid bone

Action: Depresses mandible when hyoid is fixed; elevates and protracts hyoid when mandible is fixed

Question 11

Genioglossus

Answer 11

Origin: Superior mental spine on posterior surface of mental protuberancde

Insertion: Inferior surface of tongue from root to apex

Action: Unilateral action draws tongue to one side; bilateral action depresses midline of tongue or protrudes tongue

Question 12

Hyoglossus

Answer 12

Origin: Body and greater horn of hyoid bone

Insertion: Lateral and inferior surfaces of tongue

Action: Depresses tongue

Question 13

Masseter

Answer 13

Origin: Zygomatic arch

Insertion: Lateral surface of madibular ramus and angle

Action: Elevation of the mandible, with smaller roles in protraction, retraction, and lateral and medial excursion

Question 14

Temporalis

Answer 14

Origin: Temporal lines and temporal fossa of cranium

Insertion: Coronoid process and anterior border of madibular ramus

Action: Elevation, retraction, and lateral and medial excursion of the mandible

Question 15

Mylohyoid

Answer 15

Origin: Mylohyoid line near inferior margin

Insertion: Hyoid bone

Action: Spans mandible from side to side and forms floor of mouth; elevates floor of mouth in initial stage of swallowing

Question 16

Digastric, anterior belly

Answer 16

Origin: Mastoid notch of temporal bone; digastric fossa of mandible

Insertion: Hyoid bone via fascial sling

Action: Depresses mandible when hyoid is fixed; opens mouth widely, elevates hyoid when mandible is fixed

Question 17

Digastric, posterior belly

Answer 17

Origin: Mastoid notch of temporal bone; digastric fossa of mandible

Insertion: Hyoid bone via fascial sling

Action: Depresses mandible when hyoid is fixed; opens mouth widely, elevates hyoid when mandible is fixed

Question 18

Platysma

Answer 18

Origin: Fascia of deltoid and pectoralis major

Insertion: Mandible; skin and subcutaneous tissue of lower face

Action: Draws lower lip and angle of mouth downward in expressions of horror and surprise; aid in opening mouth widely

Question 19

Orbicularis oris

Answer 19

Origin: Modiolus of mouth

Insertion: Submucosa and dermis of lips

Action: Encircles mouth, closes lips, protrudes lips as in kissing; used for speech

Question 20

Zygomaticus major

Answer 20

Origin: Zygomatic bone

Insertion: Superolateral angle of mouth

Action: Draws angle of mouth upward and laterally in laughing

Question 21

Mentalis

Answer 21

Origin: Mandible near inferior incisors

Insertion: Skin of chin at mental protuberance

Action: Elevates and protrudes lower lip (pouting); elevates and wrinkles skin of chin

Question 22

Orbicularis oculi

Answer 22

Origin: Lacrimal bone; adjacent regions of frontal bone and maxilla, medial angle of eyelids

Insertion: Upper and lower eyelids; skin around margin of orbit

Action: Sphincter of teh eyelids; closes eye in blinking, squinting, and sleep; aids in flow of tears across eye

Question 23

Risorius

Answer 23

Origin: Zygomatic arch; fascia near ear

Insertion: Modiolus

Action: Draws angle of mouth laterally in expressions of laughing, horror, or disdain

Question 24

Buccinator

Answer 24

Origin: Alveolar processes on lateral surfaces of mandible and maxilla

Insertion: Obicularis oris; submucosa of cheek and lips

Action: Compresses cheek against teeth and gums; directs food between molars; retracts cheek from teeth when mouth is closing; expels air and liquid

Question 25

Frontalis

Answer 25

Origin: Galea aponeurotica

Insertion: Subcutaneous tissue of eyebrows

Action: Elevates eyebrows, draws scalp forward

Question 26

Galea aponeurotica

Answer 26

Not a muscle, but a broad aponeurosis spanning the top of the cranium betwen the frontalis and occipitalis

Question 27

Occipitalis

Answer 27

Origin: Superior nuchal line and temporal bone

Insertion: Galea aponeurotica

Action: Retracts scalp, fixes galea aponeurotica so frontalis can act on eyebrows