This document summarizes the muscles of facial expression. It describes the 17 muscles innervated by the facial nerve, including their origins, insertions, actions, and roles in facial expressions like smiling and frowning. It also discusses the cutaneous innervation and damage to upper and lower motor neurons can cause facial paralysis on one side of the face. A lesion of the facial nerve causes complete paralysis of all muscles on the affected side of the face.

2. MUSCLES OF FACIAL EXPRESSION
 Generally from skull to skin
 Innervated by facial nerve
(CN VII)
 Sphincters and dilators
around mouth (lips), eyes,
nostrils

3. TERMINOLOGY
 “Levator. . .” - Raises
 “Depressor. . .” - lowers
 “Major” – the larger
 “Minor” – the smaller
 “Superioris” – superior
 “Inferiorioris” – inferior
 “Orbicularis” - encircles

4. There are 17 Muscles
1. Frontal Belly Of Occipitofrontalis
2. Corrugator Super cilia
3. Orbicularis Occuli
4. Compressor Naris
5. Dilator Naris
6. Procerus
7. Depressor Septi
8. Nasalis
9. Buccinator

5. 1. Zygomaticus Major and Minor
2. Levator labii Superioris alaeque nasi
3. Depressor anguli oris
4. Levator Anguli Superioris
5. Depressor Labii Inferioris
6. Orbicularis Oris
7. Risorius
8. Mentalis

6.  Frontal Belly of Ocipito
frontalis:
 Orgin : Galea
Aponeurotica
 Insertion: Orbicularis
oculi and adjacent skin
 Action: Draws scalp
forward and raises
eyebrows
MUSCLES OF FACIAL EXPRESSION

7. MUSCLES OF EYE
 Orbicularis oculi
 Sphincter muscle of eyelid
 O: frontal & maxillary bones
 I: tissue of eyelid
 Action: closes eye
 Nerve: facial / CN VII

8. MUSCLES AROUND THE NOSE
 Procerus - wrinkles skin
of nose
 Compressor nares –
lateral to bridge of nose
compresses nasal
cartilage.
 Dilator nares - lateral to
nostrils – dilates

9. MUSCLES OF FACIAL EXPRESSION
 Zygomaticus
 Orgin: zygomatic bone
 Insertion: corners of mouth
 Action: smiling
 Nerve: facial / CN VII

10. MUSCLES AROUND THE MOUTH
 Numerous dilators
(levators/depressors of
upper/lower lip and angle of
mouth)
 Buccinator
 Sphincter: Orbicularis oris
Surrounds/closes mouth

11.  Buccinator
Orgin: Maxilla and
Mandible
Insertion: Angle of
the mouth
Action: Retracts
angle of mouth
MUSCLES OF FACIAL EXPRESSION

12. Common Facial Expressions
 Smiling & Laughing: Zygomatics Major
 Sadness: Levator Labii Superioris and Levator
Anguli Oris
 Grief: Depressor Anguli Oris
 Anger: Dilator Naris & Depressor Septi
 Frowning: Corrugator Supercilii & Procerus
 Horror, Terror & Fight: Platysma
 Surprise: Frontalis
 Doubt: Mentalis
 Grinning: Risorius
 Contempt: Zygomatic Minor

13. SMILING MUSCLES FROWNING MUSCLES
 Orbicularis Oculi: close
eyelid
 Nasalis: compress/dilate
nasal openings
 Levator Labii Superioris:
raise upper lip
 Levator Anguli Superioris:
raise angle of mouth
upward
 Zygomaticus: draw angle
of mouth upward
 Risorius: draw angle of
mouth laterally
 Frontalis: elevate
eyebrows
 Orbicularis Oris: closes
mouth
 Depressor Anguli Oris:
draw angle of mouth
downward
 Depressor Labii Inferioris:
lowers lower lip
 Mentalis: draws chin up
 Platysma: draws lower lip
down & back

14. Facial Muscles – Surprise
 Epicranial: Raises forehead, pulls scalp
backward
Fig 4-7

15. Facial Muscles – Closing Eyelid
 Orbicularis oculi: Closes eyelid
Fig 4-9

16. Facial Muscles – Frowning
 Corrugator supercilii:
Draws eyebrow
medially

17. Facial Muscles – Closing Lips
 Orbicularis oris: Closes or purses lips

18. Facial Muscles – Assist Chewing
 Buccinator: Moves “bolus” of food

19. Facial Muscles – Opening
 Risorius: Smile
widely

20. Facial Muscles – Raising Upper Lip
 Levator labii superioris: Raises upper lip

21. Facial Muscles – Raising Upper Lip
 Levator labii
superioris
alaeque
nasi: Raises
upper lip and
widens
nostril

22. Facial Muscles – Smiling
 Zygomatic
us major:
Draws
cheek back
and corner
of mouth
open

23. Facial Muscles – Raising Upper Lip
 Zygomaticus
minor:
Raises upper
lip

24. Facial Muscles – Smiling
 Levator
anguli
oris:
Raises
angle of
mouth

25. Facial Muscles – Frowning
 Depresso
r anguli
oris:
Lowers
angle of
mouth

26. Facial Muscles – Lowering Lower Lip
 Depressor
labii
inferioris:
Lowers
lower lip

27. Facial Muscles – Raising Chin
 Mentalis:
Raises chin,
protrudes
lower lip,
and
Decreases
depth of
lower
vestibule.

28. Facial Muscles – Grimacing
 Platysma:
Raises
skin of
neck and
lowers
corner of
mouth.

30. CUTANEOUS INNERVATION OF FACE
 Branches of trigeminal
nerve (CN V):
 Ophthalmic (V1)
 Maxillary (V2)
 Mandibular (V3)
 Cervical plexus branches
(C2)
 Lesser occipital
 Great auricular
 Greater occipital nerve
(dorsal ramus of C2)

32. MUSCLES & NERVE SUPPLY
motor nerve supply of facial muscles
are by branches of facial nerve
 Orbicularis oculi Temporal and
zygomatic branches
 Muscles of Upper Lip and Buccal Branch
Buccinator, Levator Anguli Oris
 Risorius and Mandibular Branch
muscles of lower lip
 Platysma Cervical Branch

34. Damage to UMNs, LMNs, or facial nerve
 Clinical testing: raise eyebrows, close eyes tightly, smile
 Unilateral UMN: contralateral lower 1/2-2/3 of face
paralysed
 Unilateral LMN or CN VII: entire ipsilateral face paralysed
(Bell’s palsy)
 Lack of blinking
 Leaky mouth
 Speech difficulties
 (other CN VII functions)

35. A lesion involving the nuclear or infranuclear
portion of the facial nerve will produce a
peripheral facial palsy.
 If all motor components are involved, there is
complete paralysis of all facial muscles on the
involved side.
 The brow is smooth
 the eye does not close
 the nasolabial fold is flat
 side of the mouth droops
 There is no movement at all

36.  Idiopathic: Bell's palsy may strike at any
age, often after a mild viral illness.
Recovery is over a period of weeks to
months and is variable. The cause of the
idiopathic variety is unknown.