Muscles of facial expression - its nerve innervation & aplllied anatomy

1. NERVE INNERVATIONS
&
ITS APPLIED ANATOMY
Seminar By,
Dr. Jacob Abraham
Dept. Of Orthodontics
S.R.M. Dental College,
Chennai, India

2. The face is the mirror of the mind, and eyes without
speaking confess the secrets of the heart.
St. Jerome

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

4.  There are 17 Muscles
2. Frontal Belly Of Occipitofrontalis
3. Corrugator Super cilia
4. Orbicularis Occuli
5. Compressor Naris
6. Dilator Naris
7. Procerus
8. Depressor Septi
9. Nasalis
10. Buccinator
11. Zygomaticus Major and Minor
12. Levator labii Superioris alaeque nasi
13. Depressor anguli oris
14. Levator Anguli Superioris
15. Depressor Labii Inferioris
16. Orbicularis Oris
17. Risorius
18. Mentalis

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

6. MUSCLES AROUND THE EYE
 Sphincter: Orbicularis oculi
(Orbital, palpebral and
lacrimal parts)
 Blink (spread tears across
cornea) and close eyes tightly
 Note: elevators of upper lid
innervated by CN III,
sympathetics

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 Major an
d Minor
 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. MUSCLES OF MOUTH
Modiolus –Knitting of muscle fibers

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

13. Buccinator Muscle
 Superior Pharyngeal
Constrictor (SC)
 Pterygomandibular raphe (PR)
 Middle Pharyngeal Constrictor
(MC)
 Tonsillar Branch Of Facial
Artery (1)
 Glossopharyngeal nerve (2)
 Stylohyoid ligament (3)
 The pterygomandibular raphe
serves as an insertion point for
two muscles:
 Superior constrictor and
Buccinator

14. 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

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

17. 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)

19. MUSCLES & NERVE SUPPLY
 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

20. FACIAL NERVE
 It has both Efferent component and
Afferent component
 Efferent component supplies all the
muscles and the glands such as the
 Lacrimal gland
 Submandibular gland
 Sublingual gland
 Afferent component supplies the
 Taste sensation of the Ant.2/3rd of the tongue

21. Innervation Of Muscles Of Facial Expression:
Facial N. (VII)
 LMNs in facial nucleus is in inferior pons
 Fibres course around abducens nucleus - internal genu
 Exits brainstem at cerebellopontine angle with CN VIII

22. Course of facial nerve (CN VII)
 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)
 Exits skull via stylomastoid foramen, most
branches go through parotid gland
 Temporal
 Zygomatic
 Buccal
 Marginal mandibular
 Cervical
 Posterior auricular

24. 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)

25.  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, and that side
of the mouth droops. There is no movement at
all. The paradigm of this type of involvement is
Bell's palsy.
 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.

26. Applied Anatomy For Orbicularis Oculi
 If any injury to the nerve which supplies that
muscle, it will lead to paralyses of that muscle.
This causes the dropping of lower eyelid ,
called as “Ectropion’’ and
 Spilling of tears , called as “Epiphora”.
 Some times there will be radiating wrinkles at
the angle of the eye during strong closure. This
called as “Crow’s Feet”

27.  Risorisus Sardonicus:
 Smile in tetanus
 It is the smile like feature in agony due to
pulling of the muscles of the angle

28. References
 Cunningham’s Manual of
Practical Anatomy
 B.D. Chaurasia
 Gray’s Anatomy
 Internet