H and N 1.2

Question 1

What is the origin of the frontal belly of occupitofrontlais muscle?

Answer 1

• No bony origin
• Fibres arise form the superficial fascia and are continuous with 2 other anterior facial muscles, the procures and the corrugated supercilli

Question 2

What is the insertion of frontal belly of the occipitofrontalis muscle?

Answer 2

1. The fibers of the frontal belly are directed upward

2. They join the epicranial aponeurosis (galea aponeurotica) anterior to the coronal suture.

Question 3

What is the action of frontal belly of the occipitofrontalis muscle?

Answer 3

elevates the eyebrows and wrinkles the forehead, as when a person looks surprise

Question 4

What is the innervation of frontal belly of the occipitofrontalis muscle?

Answer 4

Terminal branches of the facial nerve; temporal branch

Question 5

What is this epicranius muscle?

Answer 5

1. This epicranius muscle consists largely of the frontal and occipital bellies and an intervening epicranial aponeurosis (galea aponeurotica).
2. As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia
3. These muscles vary from person to person, and they often blend together

Question 6

Where are all the muscles of facial expression derived embryologically from?

Answer 6

The 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII)

Question 7

What is Bell’s palsy?

Answer 7

• Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell’s palsy.
• In Bell’s palsy, paralysis of the frontalis portion of the epicranius muscle would result in an inability to fully raise one’s eyebrows and wrinkle the forehead skin.

Question 8

Where does the Occipital belly of the occipitofrontalis muscle arise from?

Answer 8

from the lateral two-thirds of the superior nuchal line of the occipital bone and the mastoid process of the temporal bone

Question 9

What is the insertion of the Occipital belly of the occipitofrontalis muscle?

Answer 9

Occipital belly of occipitofrontalis muscle inserts into the epicranial aponeurosis (galea aponeurotica)

Question 10

What is the action of the Occipital belly of the occipitofrontalis muscle?

Answer 10

• The occipital and frontal bellies of the epicranial muscle act alternately to draw the skin of the scalp back or forward.
• Individually, the occipitalis draws the scalp backward

Question 11

What is the innervation of the Occipital belly of the occipitofrontalis muscle

Answer 11

Terminal branches of the facial nerve; posterior auricular branches

Question 12

What does the extensive epicranial aponeurosis do?

Answer 12

• The extensive epicranial aponeurosis, which is called the galea aponeurotica, connects the frontal belly and occipital belly of the epicranial muscle.
• As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia. These muscles vary from person to person, and they often blend together
• In Bell’s palsy, paralysis of the occipitalis portion of the epicranius muscle would result in an inability to draw the skin of the scalp backward.

Question 13

Where does the Orbicularis oculi muscle arise from?

Answer 13

arises from the nasal portion of the frontal bone, the frontal process of the maxilla, the lacrimal bone, and the medial palpebral ligament

Question 14

Where does the Orbicularis oculi muscle attach?

Answer 14

to the skin of the eyelids, surrounds the bony orbit, and inserts into the superior and inferior tarsi medial to the lacrimal puncta

Question 15

What is the action of Orbicularis oculi muscle?

Answer 15

• a sphincter that closes the eyelids
• Its palpebral portion closes the lids gently, as in blinking
• The orbital portion closes the eyelids more forcibly.

Question 16

What is the innervation of Orbicularis oculi muscle?

Answer 16

Terminal branches of the facial nerve; primarily the temporal and zygomatic branches

Question 17

What are the three parts of the Orbicularis oculi muscle?

Answer 17

1. an orbital part, which is thicker and surrounds the orbital margin
2. a palpebral part, which is thin and lies in the eyelids
3. a lacrimal part
   - As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia

Question 18

What would paralysis of Orbicularis oculi muscle cause in Bell’s palsy?

Answer 18

In Bell’s palsy, paralysis of the orbicularis oculi would result in an inability to wink or close the eyelid ipsilaterally, with the potential for damage to the cornea because the tear film would not be evenly distributed across the cornea’s surface

Question 19

Where does the Orbicularis oris muscle arise from?

Answer 19

fibers arise near the median plane of the maxilla above and from the mandible below and from the perioral skin

Question 20

Where does the Orbicularis oris muscle insert?

Answer 20

Fibers of the orbicularis oris muscle insert into the skin of the lips and into the mucous membrane beneath the lip

Question 21

What is the action of Orbicularis oris muscle?

Answer 21

• acts primarily to close the lips. Its deep and oblique fibers pull the lips toward the teeth and alveolar arches
• When all of its fibers act together, they can protrude the lips.

Question 22

What is the innervation of Orbicularis oris muscle?

Answer 22

Terminal branches of the facial nerve; primarily the buccal and mandibular branches

Question 23

Where is the Orbicularis oris muscle derived from and why is it important?

Answer 23

1. A major portion of the orbicularis oris muscle is derived from the buccinator and blends with other facial muscles around the oral cavity
   2 This muscle is especially important in speech because it alters the shape of the mouth.
2. As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia

Question 24

What would the Orbicularis oris muscle act like in Bell’s palsy?

Answer 24

In Bell’s palsy, paralysis of the orbicularis oris would result in an inability to ipsilaterally purse the lips, as in kissing someone, or protrude the lips

Question 25

Where do buccinator muscles arise from?

Answer 25

arises from the mandible, pterygomandibular raphe, and alveolar processes of the maxilla and mandible

Question 26

What is the insertion of buccinator muscle?

Answer 26

attaches to the angle of the mouth.

Question 27

What is the action of buccinator muscles?

Answer 27

• Contraction of the buccinator muscle presses the cheek against the molar teeth and aids in chewing
• This muscle also can expel air from the mouth, as when a musician plays a woodwind or brass instrument.

Question 28

What is the innervation of buccinator muscles?

Answer 28

Terminal branches of the facial nerve; buccal branch

Question 29

How does the buccinator hold food? When would it be well developed?

Answer 29

• By pressing the cheek against the teeth, the buccinator holds food between the molars
• When the muscle contracts too forcefully during chewing, the teeth bite the cheek.
• This muscle may be well developed in a musician who plays a brass instrument.
• The buccinator is a muscle of facial expression.
• Fibers of the buccinator muscle blend with other muscles around the mouth.

Question 30

What would paralysis of the buccinator muscles be like in bell’s palsy?

Answer 30

In Bell’s palsy, paralysis of the buccinator muscle would result in an inability to ipsilaterally suck one’s cheek inward

Question 31

Where does the Platysma muscle arise from?

Answer 31

arises from the superficial fascia covering the superior portions of the pectoralis major and deltoid muscles

Question 32

What is the insertion of the Platysma muscle?

Answer 32

• ascends over the clavicle and is directed medially to insert into the mandible below the oblique line
• Other portions of the muscle insert into the skin and subcutaneous tissue of the lower portion of the face

Question 33

What is the action of the Platysma muscle?

Answer 33

• draws the lower lip and corner of the mouth inferolaterally and partially opens the mouth, as during an expression of surprise
• When all the fibers act together, the skin over the clavicle and lower neck is wrinkled and drawn upward toward the mandible.

Question 34

What is the innervation of the Platysma muscle?

Answer 34

• Terminal branches of the facial nerve; cervical branch

- As a muscle of facial expression, the cutaneous platysma muscle lies within the layers of the superficial fascia

Question 35

How would the Platysma muscle act in Bell’s palsy?

Answer 35

-paralysis of the platysma muscle would result in an inability to ipsilaterally draw the corner of the lip downward and tense the skin of the neck between the clavicle and the mandible. -The platysma also covers the anterior muscles of the neck

Question 36

What is the origin of the levator palpebrae superioris muscle?

Answer 36

Arises from the lesser wing of the sphenoid bone, anterior and superior to the optic canal

Question 37

What is the insertion of the levator palpebrae superioris muscle?

Answer 37

Attaches to the skin and tarsal plate of the upper eyelid

Question 38

What is the action of the levator palpebrae superioris muscle?

Answer 38

Raises the upper eyelid

Question 39

What is the innervation of levator palpebrae superioris muscle?

Answer 39

1. Oculomotor nerve (CN III)
2. At the distal end of this muscle, near its attachment to the tarsal plate, is a small amount of smooth muscle called the superior tarsal muscle
3. The fibers of the superior tarsal muscle are supplied by postganglionic sympathetic fibers of the autonomic nervous system.

Question 40

What is the danger of drooping?

Answer 40

1. Because of the dual nature of the levator palpebrae superioris muscle (it is skeletal and has a small smooth muscle component), drooping of the upper eyelid can result from a nerve lesion affecting the oculomotor nerve or the sympathetic fibers
2. This drooping is called ptosis

Question 41

What is ptosis?

Answer 41

1. Ptosis can result from nerve damage at 2 different sites
2. Damage to the oculomotor nerve (CN III) can result in paralysis of the levator palpebrae superioris muscle and significant ptosis
3. Damage anywhere along the sympathetic pathway from the upper thoracic sympathetic outflow to the head, the cervical sympathetic trunk, or the superior cervical ganglion and beyond can result in denervation of the small tarsal muscle (smooth muscle) that is found at the free distal margin of the levator palpebrae superioris muscle
4. This will result in a mild ptosis: the ipsilateral upper eyelid droops, but only slightly

Question 42

Where do the 4. rectus muscles and superior oblique arise from?

Answer 42

1. a common tendinous ring (anulus of Zinn) on the body of the sphenoid bone
2. The inferior oblique arises from the floor of the orbit, lateral to the nasolacrimal fossa.

Question 43

Where do the 4 rectus muscles insert?

Answer 43

-Into sclera just posterior to corner

Question 44

What does the superior oblique muscle pass?

Answer 44

-Passes forward and its tendon passes through a fibrous ring (trochela) and inserts into the sclera deep to the superior rectus muscle

Question 45

Where does the inferior oblique insert?

Answer 45

-Inserts into sclera deep to lateral rectus muscle

Question 46

What do these different eye muscles do?

Answer 46

• when the eye is abducted:
  1. the superior rectus elevates the globe
  2. the inferior rectus depresses it
• when the eye is adducted
  1. the superior oblique depresses the globe 2.the inferior oblique elevates it
• The medial rectus is a pure adductor
• The lateral rectus is a pure abductor
• The anatomic actions differ from the actions tested for clinical evaluation of the muscles

Question 47

What are these muscles innervated by?

Answer 47

1. The lateral rectus is innervated by the abducens nerve (CN VI)
2. The superior oblique is innervated by the trochlear nerve (CN IV)
3. All the other rectus muscles and the inferior oblique are innervated by the oculomotor nerve (CN III)

Question 48

What does Ipsilateral abducent nerve palsy result in?

Answer 48

The patient’s inability to fully abduct the ipsilateral eye

Question 49

What does Ipsilateral trochlear nerve palsy will result in?

Answer 49

the patient’s inability to adduct and depress the ipsilateral eye, resulting in diplopia (double vision) when going down stairs

Question 50

What does third nerve palsy result in?

Answer 50

Third nerve palsy will result in ptosis, a dilated pupil, and an inability to adduct the eye (at rest, the affected eye will be directed down and out)