The document discusses the muscles of facial expression (mimetic muscles) that are innervated by the facial nerve (cranial nerve VII). It describes the various muscle groups - orbicular, nasal, oral and others. It details each individual muscle, their origin, insertion and function. The document also discusses applied anatomy concepts like Bell's palsy, Parkinson's disease, Ramsay Hunt syndrome and others where these facial muscles are involved. It provides clinical features and diagnostic evaluation for certain conditions. Overall, the document is a detailed overview of the facial expression muscles, their function and involvement in various clinical scenarios.

1. MUSCLES OF FACIAL
EXPRESSION
Dr. A. Neeharika
Ist year PG 1

2. Contents
• Introduction
• Various muscles and their action
• Their Innervation
• Applied anatomy
2

3. Introduction-Mimetic Muscles
• The facial muscles are a group of striated skeletal muscles innervated by
the facial nerve (cranial nerve VII) which control facial expression. These
muscles are also called mimetic muscles.
• Facial Expressions- movements of mimetic musculature of the face
3

4. • The facial musculature is fairly unique. They include the only somatic
muscles in the body attached on one side to bone and the other to skin;
thus facial movements are specialized for expression.
• The face is also one of the few places in the body where some muscles
are not attached to any bone at all (e.g., orbicularis oculi, the muscle
surrounding the eyes; orbicularis oris, the muscle in the lips).
• They also act as sphincters and dilators of the orifices of the face
• Facial muscles develop from second pharyngeal arch.
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5. Groups
• For logical understanding, they are grouped as:
1. Orbicular Group
2. Nasal Group
3. Oral Group
4. Other muscles or groups
5

6. Orbicular Group
6

7. Orbicularis Oculi:
Closes and squints the eye.
Wink, concern, perplexion.
Levator Palpebrae Superioris:
Elevates the upper eyelid.
Surprise, fear
Corrugator Supercilii:
Draws the eyebrow
inferomedially and shows
anger, concern 7

8. Nasal Group
8

9. Nasalis:
Maxilla to the cartilage of the nose
and the oppositeside nasalis muscle.
Compresses the nares.
Procerus:
Fascia and skin medial to the
eyebrow to the fascia and skin over
the nasal bone (disdain look)
Depressor Septi Nasi:
From medial fiber of dilator naris muscle
to mobile part of nasal septum.
Depresses septum and narrows nostril 9

10. Oral Group
10

11. Levator labii superioris :
Infraorbital head & zygomatic head to
upper lip. Raises upper lip; helps form
naso -labial furrow. Disgust, smugness
Levator labiisuperioris alaeque nasi :
Frontal nasal process to one to ala &
other to orbicularis oris.Raises upper lip
and opens Nostril. anger, contempt
Levator anguli oris :
Maxilla below infraorbital foramen &
canine fossa to angle of mouth. Elevates
the angle of the mouth. smile, sneer,
“Dracula” expression 11

12. Zygomaticus major:
From zygomatic bone & arch to angle of
mouth. Draws the corner of the mouth
upward and laterally. Smile, laugh
Zygomaticus minor:
From zygomatic bone & medial to
zygomatic major to nasolabial groove.
Draws the upper lip upward. Smile &
Smugness.
Risorius:
From superficial fascia over parotid to
skin & mucosa on angle of lip. Retracts
corner of mouth. Grin, smile, laugh
12

13. Depressor anguli oris / triangularis:
From oblique line of mandible to angle
of mouth. Draws corner of mouth down
and laterally.
Depressor labii inferioris :
From base of mandible to skin n mucosa
of lower lip. Draws lower lip downward
and laterally. Sadness, uncertainty, dislike
Mentalis :
From mandible below lower incisors to
skin of chin. Raises and protrudes lower
lip as it wrinkles skin on chin. doubt,
pout, disdain 13

14. Orbicularis Oris:
From buccinator muscle to angle of
mouth (upper lip) and mandible
(lower lip). Closes lips; protrudes lips.
puckering, whistling
Buccinator :
From alveolar process f max. and mand. In
region of molars & pterygomandibular
ligament. Presses the cheek against teeth;
Compresses distended cheeks. pucker,
exertion, sigh
Platysma :
From skin and superficial fascia of pectoral
and deltoid region to lower border of
mandible. Draws up the skin of the superior
chest and neck. Creature from Black Lagoon”
expression 14

15. Other Group
15

16. Occipitofrontalis :
Frontal Belly:
From ant. Part of
Galea aponeurotica to
Skin on lower part
of forehead.
Wrinkles forehead;
Raises eyebrows
Anterior auricular: Draws ear
upward and forward
Occipital belly:
From lateral 2/3rd of
Superior nuchal line
To post. Part of
galea Aponeurotica.
Draws scalp
backward
Superior auricular : Elevates ear
Posterior Auricular: Draws ear
upward and backward
16
Cannot
consciously
move.
Temperoparietali
s has to be
checked.

17. Nerve Supply
17

18. Facial N. (VII)
• LMNs in facial nucleus is in inferior pons
• It emerges from the brainstem between the pons and the medulla, and
controls the muscles of facial expression
• The facial nerve is developmentally derived from the hyoid arch (second
pharyngeal branchial arch). The motor division of the facial nerve is
derived from the basal plate of the embryonic pons, while the sensory
division originates from the cranial neural crest.
Course:
• Fibres course around abducens nucleus - internal genu Exits
brainstem at cerebellopontine angle with CN VIII Through the
petrous part of the temporal bone Through internal acoustic meatus
with CN VIII Into facial canal, along walls of the tympanic cavity
(external genu of facial nerve, geniculate ganglion)
18

19. Exits skull via stylomastoid foramen, most branches go through parotid
gland
• Temporal
• Zygomatic
• Buccal
• Marginal mandibular
• Cervical
• Posterior auricular
• The oculomotor nerve [III], which innervates the levator palpebrae
superioris; sympathetic fibers, which innervate the superior tarsal
muscle.
19

20. • http://emedicine.medscape.com/article/1289
133-overview
• http://emedicine.medscape.com/article/8352
86-overview#a30
20

21. 21

22. Applied Anatomy
22

23. Bell’s Palsy
• Charles Bell in 1821 first described Bell’s Palsy.
• It is Common, acute, benign neurological disorder, characterized by
sudden, isolated peripheral facial nerve paralysis
• Bell’s Palsy- Lower Motor Neuron Disorder.
• Various and unknown etiology
• However infectious, genetic, metabolic, autoimmune, vascular condition,
and nerve entrapment, viral etiology
23

24. Clinical Features:
• Can be complete/ partial- only lower part of face is involved
• Lack of facial expressions on one side
• Patient is also unable to whistle, smile or grimace
• Increased lacrimation, hypersensitivity to sound (hyperacusis), loss of
taste / metallic taste(chordatympani) and pain near mastoid area (70%
of patients)
• Sudden facial weakness, difficulty with articulation, inability to keep an
eye closed.
24

25. • Clinical Evaluation:
– Exclude etiologies like trauma, otologic disease, and intracranial
– History- onset, course, duration
– Facial creases, nasolabial fold- dissapear
– Forehead unfurrows and corner of mouth droops
– Eyelids will not close, and lower lid sag
- Tear production decreases, but
appears to tear excessively as loss
of eye lid control
- Postive Hitselberger sign-
decreased sensation along the
external acoustic meatus.
25

26. Diagnostic evaluation
• Determine whether it is central or peripheral
– Peripheral facial palsy involves all the facial muscles ipsilateral to the
side of facial nerve involvement
– Central involves facial muscles contralateral to the lesion in the brain
stem above pons and cerebral hemisphere.
• Familial history
• Sudden onset or gradual
26

27. • Physical examination to rule of Ramsay-Hunt syndrome
• Serological tests like ELISA and PCR to rule out
• Virological Analysis of endoneurial fluid obtained during decompression
surgeryrevelaed HSV-1 in 11 of 14 Bells’ Palsy Patients.*
*Gliden DH. Bell’s Palsy. N Engl J Med 2004:23;1323-31
• Electric test like Trans Temporal stimulation electromyography –
presence of voluntary motor unit indicates continuity of nerve.
• Nerve Excitability test
• Trigeminal blink reflex is the only test to measure the intracranial
pathway of facial nerve
• Conventional radiographs, CT, MRI
Indian J Stomatol 2013;4(1):36-39
27

28. INFRANUCLEAR LESIONS (LMNs) SUPRANUCLEAR LESIONS (UMNs)
LMN lesion of facial nerve (Bell’s
Palsy), the whole of the face of the
same side gets paralyzed.
The face becomes assymetrical and is
drawn up to normal side.
The affected side is motionless.
Wrinkles disappear and eye cannot
be closed.
Peripheral Palsy
UMN lesions of Facial nerve is
usually a part of hemiplegia.
Only the lower part of opposite side
of the face is paralyzed.
The upper part of frontalis and
orbicularis oris escapes due to its
bilateral representation in the
cerebral cortex.
Central Palsy
28

29. Orbicularis oculi
• If any injury to the nerve supllying orbicularis oculi, it will cause paralysis
of that muscle. This causes of drooping of the lower eyelid, called as
‘Ectropion’.
• Spilling of tears is called “Epiphora”.
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30. Tetanus
• Tetanus is a clinical diagnosis characterized by a triad of muscle rigidity,
muscle spasms and autonomic instability.
• Clostridium tetani spores enter into the body through any abrasions on
the skin.
• Release tetanospasmin (potent neurotoxin)
C/F:
• Early symptoms of tetanus include neck stiffness, sore throat, dysphagia
and trismus.
• Spasm extending to the facial muscles causes the typical facial
expression, ‘risus sardonicus’.
• Truncal spasm causes opisthotonus.
Continuing Education in Anaesthesia, Critical Care & Pain | Volume 6 Number 3 2006
30

31. Parkinson’s Disease
• Parkinson’s disease (PD) is a chronic, progressive, neurodegenerative
disorder .
• Characterized by resting tremors, cogwheel rigidity, bradykinesia.
• PD results from idiopathic degeneration of dopaminergic cells in the
pars compacta of substantia nigra
Depletion of neurotransmitter dopamine in the basal ganglia
• The four cardinal signs of PD are
resting tremor, rigidity or stiffness,
bradykinesia and postural instability.
31

32. Congenital
• Mobius Syndrome
• It is an extremely rare congenital neurological disorder which is
characterized by facial paralysis and the inability to move the eyes from
side to side. Most people with Möbius syndrome are born with complete
facial paralysis and cannot close their eyes or form facial expressions. Limb
and chest wall abnormalities sometimes occur with the syndrome.
32

33. • Melkersons-Rosenthal Syndrome
It is a rare neurological characterized by recurring facial paralysis,
swelling of the face and lips (usually the upper lip), and the development
of folds and furrows
33

34. • Ramsay Hunt Syndrome:
Peripheral facial nerve palsy
May be unilateral or bilateral
Vesicular rash on ear
Ear pain, tingling, tearing, loss of sensation and nystagmus.
• Ramsay Hunt Syndrome Type II:
Reactivation of latent Herpes zoster virus within the dorsal root ganglion
of facial nerve is associated with vesicles affecting ear canal.
34

35. References:
• Text Book of anatomy- Inderbir Singh
• Text of anatomy- B.D. Chaurasia
• Cunningham Manual of Anatomy
• Facial Palsy: A Review- Indian J Stomatol 2013;4(1):36-39
• Continuing Education in Anaesthesia, Critical Care & Pain | Volume 6
Number 3 2006
• Continuing Education in Anaesthesia, Critical Care & Pain | Volume 6
Number 3 2006
• *Gliden DH. Bell’s Palsy. N Engl J Med 2004:23;1323-31
35