The Nose, Sinuses and Muscles of Facial Expression

Question 1

External Nose

Answer 1

-Projects outwards allowing air to enter the nasal cavity
-Made up of bone and cartilage
*nasal bones

Question 2

Nasal Cavity

Answer 2

Made up of bones, cartilage and mucous membranes

Can be divided into left and ride side:
-Midline and lateral walls
-Roof and floor
-Separated by nasal septum

Functions:
-Humidify, warm and filter air
-Facilitate drainage of paranasal sinuses
-Secrete mucous

*extends to nasopharynx where mucous will then be swallowed

Question 3

Bones of the Nasal Cavity (7)

Answer 3

1. Frontal bone
2. Ethmoid bone (and cribriform plate)
3. Sphenoid bone
   *neurocranium
4. Nasal bone
5. Vomer bone
6. Maxillary bone
7. Palatine bone
   *viscerocranium

Question 4

Borders of Nasal Cavity

Answer 4

Medial wall: Nasal septum (made up of a bony portion and cartilaginous portion)

Lateral wall: Conchae and Meatuses

Roof: cribriform plate (ethmoid), nasal bone, frontal bone and sphenoid bone

Floor: palatine and maxillary bones (palate)

Question 5

Nasal Septum

Answer 5

Made up of ethmoid bone and vomer bone (bony portion) and septal cartilage (cartilaginous portion)

Deviated nasal septum= septum that does not run across midline (bent) from hit to nose or developmental abnormality

Question 6

Conchae and Meatuses

Answer 6

Conchae:
-Superior, middle and inferior nasal concha (bones that extend to nasal cavity)
*superior and middle=processes of ethmoid, inferior= separate bone
*functions to increase surface area in nasal cavity, filters, humidifies and warms air (coated in mucous)

Meatuses:
-Superior, middle and inferior nasal meatus (openings/passages)

Question 7

External Nose Cartilages (3)

Answer 7

1. Lateral nasal cartilage
2. Major alar cartilage
3. Minor alar cartilage

Question 8

Clinical Connection: Rhinoplasty

Answer 8

Surgery that changes shape of nose, cartilages manipulated and connection b/t nasal and maxillary bone broken to change shape

Question 9

What are Paranasal Sinuses

Answer 9

-Cavities (air pockets) found in the skull
-Ethmoid, frontal, maxillary and sphenoid bones contain paranasal cavities
-Lined with respiratory mucosa and secrete mucous

Function: lighten weight of skull, humidify/head/filter air, secrete mucous

Question 10

Paranasal Sinuses (4)

Answer 10

1. Frontal sinus
2. Ethmoid sinus
3. Maxillary sinus
4. Sphenoid sinus (deeper to ethmoid)

*Superior meatus drains sphenoid and posterior ethmoid sinuses

*Middle meatus drains frontal, anterior ethmoid and maxillary sinuses

Question 11

Clinical Connection: Sinusitis

Answer 11

Inflammation of mucous membrane of one or more paranasal sinuses

-Occurs due to microbial infection (virus, bacteria, fungus), allergy or deviated septum
-Can cause blockage in drainage into nasal cavity, causes pressure to build up and cause sinus headache

Treatment: oral decongestant, spray, antibiotics, surgery

Question 12

Muscles of Facial Expression Defintion/Function

Answer 12

-Originate from facial bones or adjacent muscles
-Insert into skin
-Superficial (subcutaneous) muscles
-Innervated by CN VII (facial) nerve

Function: act as sphincters and dilators, alter facial expressions

Question 13

Muscles of Facial Expression (7)

Answer 13

1. Frontalis
2. Orbicularis Oculi
3. Corrugator Supercilii
4. Zygomaticus
5. Orbicularis Oris
6. Buccinator
7. Platysma

Question 14

Frontalis

Answer 14

-Epicranial group (occipitalfrontalis)

Acts to draw scalp back, raising the eyebrows (‘surprise’)

Question 15

Orbicularis Oculi

Answer 15

-Orbital group
1. Orbital part (more exterior) *tightly closing eye- winking

2. Palpebral part (eyelid/closer to eye) *loosely closing eye- blinking
3. Lacrimal part (corner of eye) *compress lacrimal sac- tears

Question 16

Corrugator Supercilii

Answer 16

-Orbital group

Acts to draw eyebrows together medially and inferiorly (frowning)

Question 17

Zygomaticus

Answer 17

-Oral group

Acts to pull corners of mouth up and draw it laterally (smile)

*Zygomaticus minor and major

Question 18

Orbicularis Oris

Answer 18

-Oral group

Acts to purse and protrude lips

Question 19

Buccinator

Answer 19

-Oral group

Acts to pull cheeks inward against teeth (blowing)

*under platysma

Question 20

Platysma

Answer 20

-Neck group

Acts to pull corners of mouth down (‘Yikes’)

Question 21

CNVII (Facial Nerve)- Intercranial Pathway (5 Steps)

Answer 21

1. Originates from brainstem
2. Goes through internal acoustic meatus
3. Goes through facial canal
4. Goes through medial wall of middle ear
5. Exits through stylomastoid foramen

Question 22

Facial Nerve Innervation (5 Branches)

Answer 22

1. Temporal branches:
   -Orbicularis oculi (upper half)
   -Corrugator supercilii
   -Frontalis
2. Zygomatic branches:
   -Orbicularis oculi (lower half)
3. Buccal branches:
   -Orbicularis oris
   -Zygomaticus
   -Buccinator
4. Marginal mandibular branches:
   -Lower lip/chin
5. Cervical branches:
   -Platysma

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