Muscles of facial expression and its role in prosthodontics.

1. MUSCLES OF FACIAL
EXPRESSIONS
Presented by:
Dr. Ayesha Burugpalli
MDS 1st yr
Dept of prosthodontics

2. INTRODUCTION
• Musculature is involved directly in several important phases of complete denture.
• They exert a direct influence upon the peripheral extensions, shape & thickness of
denture bases, position of teeth both horizontally & vertically and facial
appearances.
• They are active during mastication, speech and deglutition.
Following group of muscle are studied in relation to complete denture-
- muscle of mastication and its accessory muscles
- muscles of facial expressions

3. ROLE OF FACIAL MUSCLES IN COMPLETE DENTURE PROSTHESIS
Buccinator, orbicularis oris, incisivus superioris and inferioris and
bucco-labial groups are main concern to prosthodontist.

4. FACE
• BOUNDARIES
SUPERIORLY : hairline
INFERIORLY : chin and base of mandible
LATERALLY : auricle on each side
FOREHEAD IS COMMON TO BOTH SCALP AND FACE

5. FACIAL SKIN
• Highly vascular ( which makes face blush & blanch)
Wounds bleed profusely but heal rapidly.
• Rich in sebaceous and sweat glands .
• Laxity in most area of skin ( facilitates rapid spread of oedema).
• Boils in nose & ear are very painful due to fixity of skin to underlying cartilage.
• Facial skin is Very elastic & thin because the facial muscles are inserted into it.
Secrete oil Regulate body
temperature

6. SUPERFICIAL FASCIA
• Facial muscles
• Vessels & nerves
• Fat ( absent in eyelids)
DEEP FASCIA
• Absent
Present only over
parotid

7. FACIAL MUSCLES

8. • EMBRYOLOGICALLY
Develop from
mesoderm of
2nd brachial
arch
And therefore
supplied by
facial nerve.
(VII CN)

9. • MORPHOLOGICALLY
Represent the remnants of panniculus carnosus , a continuous subcutaneus muscle
sheet seen in some animals.

10. • FUNCTIONALLY
Primarily regulate 3 openings of face
1. Palpebral fissure
2. Nostrils
3. Oral fissure
Each has
• 1 sphincter (naturally circular)
• Many dilators (radial)
Palpebral
fissure
Orbicularis
occuli
Levator palpabrae
superioris .
Frontalis of occipitifrontalis
Oral fissure
Orbicularis
oris
All except
mentalis
nostrils
Compressor
naris
Dilator naris.
Depressor septi.
Levator labii superioris
alaque nasii.
SPHINCTER DILATOR

11. TOPOGRAPHICALLY – 6 HEADS
1. MUSCLES OF SCALP – Occipitofrontalis
2. MUSCLES OF AURICLE –
3. MUSCLES OF EYELIDS/ ORBITAL OPENING –
4. MUSCLES OF NOSE –
• Orbicularis occuli
• Corrugator supercilli
• Levator palpabrae superioris
• Auricularis anterior
• Auricularis superior
• Auricularis posterior
• Procerus
• Compressor naris
• Dilator naris
• Depressor septi
All these are
vestigeal

12. • 5. MUSCLES AROUND MOUTH –
• 6. MUSCLES OF NECK - Platysma
1. Levator labii superioris
alaque nasii
2. Levator labii superioris
3. Levator anguli oris
4. Zygomaticus major
5. Zygomaticus minor
6. Buccinator
7. Risorius
8. Depressor anguli oris
9. Depressor labii inferioris
10. Mentalis
11. Orbicularis oris

13. FUNCTIONAL MOVEMENTS : FIXED & MOVABLE
• For any facial movements, there must be a frame, and that frame is the skull.
• In the general region concerned with these movements, there is a fixed bone region (the upper part of
the face) and a movable bone region (the lower part of the face).
• The two points of anchorage for facial movements :
 - anterior part of the cranium
 -the sternum
 -and between them are the synergistic groups of muscles that move the skin and bone to alter
expression.
• Between these anchors, the mandible and hyoid bones are suspended.
• The two condyles of the mandible articulate with the cranium in the mandibular fossae of the
temporal bones.
• These articulations provide certain leverage advantages as well as control and limitation of mandibular
movement.

14. MUSCLES OF THE FIXED BONE REGION
• Frontalis
• Orbicularis occuli
• Corrugator supercilli
• Levator palpabrae superioris
• Procerus
• Compressor naris
• Dilator naris
• Depressor septi

15. MUSCLES OF THE MOVABLE BONE REGION
• The movable bone region may be depicted as an inverted pyramid, extending from
the sternum to the ears and then to the nose.
• It may well be called a pyramid of polyfunction since it houses the organs
responsible in whole or in part for the functions of breathing, speech, mastication,
deglutition, and facial expression .
Pyramid of
polyfunction

16. • ELEVATION
• ZYGOMATICUS
• QUADRATUS LABI SUPERIOUS
• CANINUS
• DEPRESSION
• TRIANGULARIS
• QUADRATUS LABI INFERIORIS
• PLATYSMA
Each movement of facial muscle is the result of
contraction and relaxation of the group of muscles.
• RETRACTION
• ZYGOMATICUS
• RISORIUS
• PLATYSMA
• TRINGULARIS
• BUCCINATOR
• COMPRESSESSORS
• ORBICULARIS ORIS
• INCISIVE LABI SUPERIORIS
• MENTALIS
• ORBICULARIS ORIS

17. ELEVATORS OF LIPS
• A smile is produced by the elevators of the lips, assisted by the retractors.
• As these muscles work in varying degrees, they exert a pull on the angles of the mouth, resulting in a
relaxing of the continuous fibers of the orbicularis oris, the sphincter control of the mouth.
• The lips are stretched and drawn against the teeth and tend to part and open the mouth.
• The degree of opening varies with the individual or the depth of emotion expressed. True laughter
occurs when the orbicularis oris is completely and involuntarily inhibited.
• The prosthodontic significance of a smile is the recognition that if one part of the intricate complex
which produces smiling is out of position, this affects all of the other components which make up the
smile.
• With the elevation of the maxillary lips and the retraction of the corners of the mouth, the lips are
drawn against the teeth, and the placing of these teeth becomes extremely important in forming the
backdrop for the smile.
• If the teeth are placed too far labially, the orbicularis oris is stretched and the modioli are positioned
too far anteriorly so that they are prevented from moving in the positions they were accustomed to
when natural teeth were present.
• This stretching effect of the lips against the teeth also tends to exert a dislodging force on the
maxillary denture.

18. • On the other hand, if there is lack of maxillary lip support and teeth are set on the
crest of the ridge, there is a downward cast to the smile which is similar to
expressions of grief.
• This is one of the most pitiful prosthodontic errors which can be perpetrated.
Unfortunately, it occurs frequently.

19. DEPRESSORS OF LIPS
• The expressions reflecting sadness, grief, despair, or contempt.
• The depressor muscles, acting particularly on the corners of the eyes and mouth, incline
these features of the face obliquely downward and outward.
• The rima oris is reduced in size to a narrow,with the corners slanting downward.
• This downward and outward cast appears to occur from a contraction of the depressor
muscles of the corners of the mouth.
• This is actually somewhat of an optical illusion produced by the following actions which
take place:
(1) the muscles inserted into the modioli become tense, thus fixing the modioli
(2) the triangularis(depressor anguli oris) muscles contract, drawing the corners of the
mouth downward and outward
(3) a contracting action of the mentalis muscles thrusts the mandibular lip upward
(4) the inferior part of the orbicularis oris then assists in raising the mandibular lip against
the maxillary lip.

21. OCCIPITOFRONTALIS
Two bellies & both are inserted into epicranial aponeurosis.
.occipitalis
frontalis
Origin- lateral 2/3rd of
superior nuchal line
NS- Post auricular Br
of VII CN
Origin – skin of forehead
mingling with orbicularis
occuli & corrugator
supercilli.
NS –Temporal Br of
VII CN
Both are inserted into epicranial aponeurosis.(3rd layer of SCALP)
Sup nuchal line

22. • EPICRANIAL APONEUROSIS
The galea aponeurotica (epicranial aponeurosis) covers the upper part of the cranium.
Behind, it is attached, in the interval between its union with the Occipitales, to the external
occipital protuberance and highest nuchal lines of the occipital bone; in front, it forms a short
and narrow prolongation between its union with the Frontalis.
BLOOD SUPPLY – Superficial temporal, ophthalmic , posterior auricular & occipital arteries.
Actions – raises the eyebrows & cause horizontal wrinkles.
giving the expression of surprise, amazement, doubt
or fear.
APONEUROSIS- a sheet of white fibrous tissue that takes the
place of tendon in flat muscles having a wide area of
attachment.

24. CORRUGATOR SUPERCILLI
ORIGIN- Medial end of superciliary arch
INSERTION – Skin of mid-eyebrow
BLOOD SUPPLY – Superficial temporal and ophthalmic artery.
NERVE SUPPLY – Temporal Br of VII CN
ACTIONS – Frowning , Along with orbicularis occuli it produces vertical wrinkles
on supra nasal strip of forehead. ( ex- shield the eyes in bright sunlight)
Small pyramidal muscle located at the
medial end of each eyebrow.

26. ORBICULARIS OCULI 1
`
Broad , flat elliptical muscle which surrounds the
circumference of orbit.
ORIGIN INSERTION ACTIONS
ORBITAL PART Medial part of medial palpebral ligament, frontal
process of maxilla & nasal part of frontal bone.
Concentric rings ; return
to the point of origin.
Cause forceful closure
of eyelids
(protects from bright
light , wind & rain.
PALPEBRAL Lateral part of median palpebral ligament. Lateral palpebral raphae. Closes lids gently as in
blinking and sleeping.
LACRIMAL PART Lacrimal facia & posterior lacrimal crest
Forms sheath for lacrimal sac.
Pass laterally in front of
tarsal plates of eyelids to
the lateral palpebral
raphae.
Dilates lacrimal sac for
sucking of lacrimal fluid
into the sac.
Supports lower lid
It has 3 parts:

27. • BLOOD SUPPLY – Facial, superficial temporal, maxillary & ophthalmic arteries.
• NERVE SUPPLY – Temporal & zygomatic Br of VII CN
ACTIONS
The orbicularis oculi surrounds the eye, and its contraction closes the eyelids, pulls
down the eyebrows, and raises the cheeks.
Contractions of orbicularis occuli and corrugator supercilli produce the crowfeet
wrinkles at the corners of the eyes

28. LEVATOR PALPEBRAE SUPERIORIS
• An extraocular muscle
• ORIGIN – Sphenoid bone( lesser wing)
• INSERTION – upper eyelid
• BLOOD SUPPLY – ophthalmic artery
• NERVE SUPPLY – oculomotor nerve ( III CN)
• ACTION – elevates upper eyelid

30. PROCERUS
ORIGIN : nasal bone & lateral part of lateral nasal cartilage
INSERTION : skin of forehead btw eyebrows & on bridge of nose.
BLOOD SUPPLY : terminal Br of facial artery
NERVE SUPPLY : upper buccal Br of VII CN
ACTIONS : Produce transverse wrinkles over the bridge of nose.
Active in frowing and concentration
Helps to reduce glare of bright sunlight
It is a pyramidal muscle

31. NASALIS
Compressor naris Dilator naris

32. COMPRESSOR NARIS
ORIGIN : maxilla just lateral to nose
INSERTION : aponeurosis across dorsum of nose
BLOOD SUPPLY : infraorbital Br of maxillary artery & branches of
facial artery
NERVE SUPPLY : upper buccal Br of VII CN
ACTIONS : Nasal aperture compressed
It is the transverse part of nasalis

33. DILATOR NARIS
ORIGIN : maxilla over lateral incisor
INSERTION : alar cartilage of nose
BLOOD SUPPLY :: infraorbital Br of maxillary artery & branches of
facial artery
NERVE SUPPLY : upper buccal Br of VII CN
ACTIONS : dilation of nasal aperture

35. DEPRESSOR SEPTI
ORIGIN :maxilla over central incisor
INSERTION :lower mobile part of nasal septum
BLOOD SUPPLY : Superior labial Br of facial artery
NERVE INNERVATION : upper buccal Br of VII CN
ACTIONS : Pulls nasal septum downwards flattening the philtrum of
maxillary lip and narrowing the nostril.
And with alar part of nasalis , widens the nasal aperture

37. ORBICULARIS ORIS
ORIGIN INSERTION
INTRINSIC PART
Deep stratum, very thin sheet.
Sup incisivus-maxilla
Inf incisivus- mandible
Angle of mouth
EXTRINSIC PART
Two strata , formed by
converging muscles.
Thickest middle stratum;
derived from buccinator.
Thick superficial stratum;
derived from elevators &
depressors of lips.
Lips & angle of mouth
BLOOD SUPPLY- sup & inf labial Br of facial artery.
mental & infraorbital Br of maxillary artery.
transverse facial Br of superficial temporal artery.
NERVE SUPPLY- lower buccal Br of VII CN
ACTIONS- close and protrude lips
Numerus extrinsic muscles make it most versatile for various types of grimaces.

38. THE CHEEK
• Less mobile than the lip and supported on the 3 sides by foundation that are
subjected to little change.
• The zygoma above, the mandible below, and the parotid gland overlying the
masseter muscle in the posterior region.
• Additional support is provided by subcutaneous fat and buccal fat pads.
• Which is responsible for the soft rounded contour of the cheeks in the lower third of
the face.
• Anteriorly supported is by the muscular framework converging into the modioli.
• Further support is by posterior teeth and their supporting structures.

39. • With the loss of the posterior teeth, the cheek tends to collapse in varying degree
and move medially to meet the tongue.
• The loss of the anterior teeth and VDO further alter the cheek contour.
• The looseness of the subcutaneous fat and elasticity of the CT produce the hollow
cheek in aged people.

40. LIP AND THEIR NATURAL SUPPORT
• Dependent on 2 type of support:
• A built in support made up mostly of musculature, Fibrous Connective
Tissues and glands.
• A back stop support of hard structure teeth and alveolar process.
• Muscular support is the Orbicularis oris muscle which is the functional unit of
all the muscles which make up the lip and the cheek complex.
• The support for the lip by teeth and the alveolar process is of extreme
importance not only as it affect facial appearance but also contributes to the
function of eating, speaking and breathing.
• If the condition of unsupport exist over a long period of time, the lip and the
oral fissures can become so small in size that they resemble those of the
patients with microstomatic hereditary tendency

41. MUSCLE BEHAVIOR
• The physiologic behavior of the muscles of lip and cheek is the same as that of
other skeletal muscle.
• When these muscles are well supported by the teeth they are in their most efficient
physiologic state and can contract half of their length.
• When the support is lost the distance from origin to insertion is reduced , muscle
become less efficient and they lose their ability to contract in relative proportion to
the degree of the shortening of fibres.
• Decrease in efficiency lessens the vascular supply and can result in atrophy, fibrosis /
contracture.
• On the other hand if the denture supply over support; again the musculature will be
affected.
• Stretching the muscle by as little as 0.8% of its original length , will produce a
stretch reflex response resultant muscle strain will either cause bone loss or will
make the denture intolerable to the patient.

43. BUCCINATOR
• BLOOD SUPPLY- buccal Br of maxillary artery and branches from facial artery.
• NERVE SUPPLY- lower buccal Br of VII CN
• ACTIONS- Flattens cheek against teeth & gums
Prevent accumulation of food in vestibule
whistling muscle
ORIGIN INSERTION
UPPER FIBRES Maxilla opp molar teeth Straight to upper
lip
LOWER Mandible, opp molar
teeth
Straight to lower
lip
MIDDLE Pterygomandibular
raphae
Middle fibres
decussate

44. • ROLE IN CD
• In lower jaw buccinator muscle becomes part of denture bearing area.
• The action of buccinator does not dislodge the denture directly.
• The fibres of buccinator are arranged parallel to the buccal shelf area and the fibres
of masseter are arranged oblique to this. So when the patient is asked to close the
mouth under resistance, the action of masseter on buccinator forms masseteric
ridge in the distobuccal ridge of the lower jaw. This is evident on the complete
denture impression as notch called the masseteric notch.

45. BUCCAL FRENUM
• Maxillary buccal frenum
• Anteriorly-o.oris
• Posteriorly- buccinator
• Beneath – levator anguli oris
• Incisivus superiorioris
• Mandibular buccal frenum
• Anteriorly- o.oris
• Posteriorly- buccinator
• Beneath-depressor anguli oris
• Incisivus inferioris
• Mentalis (lateral fibres)

47. LEVATOR LABII SUPERIORIS ALAQUE NASI
• ORIGIN- frontal process of maxilla
• INSERTION- upper lip & alar cartilage of nose
• BLOOD SUPPLY- Facial artery & infraorbital Br of maxillary artery.
• NERVE SUPPLY- upper buccal Br of VII CN
• ACTIONS- lifts upper lip & dilate the nostrils.

49. ZYGOMATICUS MAJOR
• ORIGIN- post aspect of lateral surface of zygomatic bone
• INSERTION- skin at angle of mouth
• BLOOD SUPPLY- superior labial Br of facial artery
• NERVE SUPPLY- zygomatic & buccal Br of VII CN
• ACTIONS- pulls the angles upward and laterally as in smiling.

51. LEVATOR LABII SUPERIORIS
• ORIGIN- Infraorbital margin of maxilla
• INSERTION- skin of upper lateral half of upper lip
• BLOOD SUPPLY- infraorbital br of maxillary artery & facial artery
• NERVE SUPPLY- zygomatic & buccal branch of facial nerve
• ACTIONS- elevates upper lip , forms nasolabial groove

53. LEVATOR ANGULI ORIS
• ORIGIN- maxilla just below infraorbital foramen
• INSERTION- skin of angle of mouth
• BLOOD SUPPLY- superior labial Br of facial artery , infraorbital Br of maxillary
artery
• NERVE SUPPLY- zygomatic & buccal Br of VII CN
• ACTIONS- elevates angle of mouth , forms nasolabial groove

55. ZYGOMATICUS MINOR
• ORIGIN- anterior aspect of lateral surface of zygomatic bone.
• INSERTION- upper lip medial to its angle
• BLOOD SUPPLY- Superior labial br of facial artery
• NERVE SUPPLY- zygomatic and buccal Br of VII CN
• ACTIONS- elevates the upper lip

57. DEPRESSOR ANGULI ORIS
• ORIGIN- oblique line of mandible below 1st molar, premolar & canine region.
• INSERTION-skin at the angle of the mouth & fuses with orbicularis oris.
• BLOOD SUPPLY- Inf labial Br of facial artery , mental Br of maxillary artery
• NERVE SUPPLY- Buccal and marginal mandibular Br of VII CN
• ACTIONS- draws angle of mouth downwards and laterally

59. DEPRESSOR LABII INFERIORIS
• ORIGIN- anterior part of oblique line of mandible
• INSERTION-lower lip at midline,fuses with muscles of opposite side
• BLOOD SUPPLY- Inf labial Br of facial artery , mental Br of maxillary artery
• NERVE SUPPLY- marginal mandibular Br of VII CN
• ACTIONS- draws lower lip downward

61. MENTALIS
• ORIGIN- mandible inferior to incisor teeth
• INSERTION- skin of chin
• BLOOD SUPPLY- Inf labial Br of facial artery , mental Br of maxillary artery
• NERVE SUPPLY- marginal mandibular Br of VII CN
• ACTIONS- elevates & protrudes lower lip as it wrinkles skin on chin

63. RISORIUS
• ORIGIN- facia on the masseter muscle
• INSERTION- skin at the angle of mouth
• BLOOD SUPPLY- Sup labial Br of facial artery
• NERVE SUPPLY- buccal Br of VII CN
• ACTIONS- retracts angle of mouth

64. Platysma is seen as a sheet of muscle by
clenching the jaws firmly.

65. PLATYSMA
• ORIGIN- upper parts of pectoral & deltoid fasciae
• INSERTION- anterior fibres – base of mandible
posterior fibres – skin of lower face and lip & may be continuous with risorius
• BLOOD SUPPLY- Branches of submental & suprascapular artery.
• NERVE SUPPLY- CERVICAL Br of VII CN
• ACTIONS- pulls the angle of mouth downwards as in Horror or fright , depresses mandible ,
releases pressure of skin on subjacent veins.
A broad sheet of muscle fibres extending from the collar
bone to the angle of the jaw.

66. MAXILLARY ARTERY

67. FACIAL ARTERY

68. SIMPLE METHOD TO MEMORIZE NERVE SUPPLY OF MUSCLES OF FACIAL EXPRESSIONS
1. MUSCLES OF SCALP – Occipitofrontalis
2. MUSCLES OF EYELIDS/ ORBITAL OPENING –
3. MUSCLES OF NOSE –
• Orbicularis occuli
• Corrugator supercilli
• Levator palpabrae superioris ( III CN )
4. MUSCLES AROUND MOUTH –
5. MUSCLES OF NECK – Platysma (Cervical Br)
1. Levator labii superioris alaque nasii
2. Levator labii superioris
3. Levator anguli oris
4. Zygomaticus major
5. Zygomaticus minor
6. Buccinator
7. Risorius
8. Depressor anguli oris
9. Depressor labii inferioris
10. Mentalis
11. Orbicularis oris
• Procerus
• Compressor naris
• Dilator naris
• Depressor septi
• Occipitalis (post auricular Br of VII CN)
• frontalis
Temporal Br of VII CN
Upper buccal Br
of VII CN
Marginal mandibular Br of VII
CN
Lower buccal Br of
VII CN

69. COMMON FACIAL EXPRESSIONS &
MUSCLES PRODUCING THEM

70. Smiling & laughing : zygomaticus major
Sadness : levator labii superioris
Depressor anguli oris

71. Frowning : corrugator supercilli & procerus
Dislike : procerus

72. Horror , terror & fright : Platysma
Surprise : frontalis

73. Whistling : buccinator , orbicularis oris
Anger : dilator naris depressor septi

74. Grinning : resorius
Doubt : mentalis

75. IMPORTANCE OF SMILE
• Smile is produced by the elevation of the lips assisted by retractors and the true laughter
occurs when the Orbicularis oris is completely and involuntarily inhibited.
• A prosthodontic significance of a smile is the recognition that if one part of this complex is
out of position will affect other components which make up the smile.
• The lips are drawn against the teeth by the elevation of the maxillary lip and the retraction of
the corner of mouth.
• So the placement of teeth become extremity important in forming the backdrop for the
smile.
• If the teeth are placed too far labially, the orbicularis oris is stretched and this effect tends to
exert a dislodging effect on the maxillary denture.
• If there is a lack of maxillary lip support and teeth are set on the crest of the ridge, there is a
downward cast to the smile which is similar to the expression of grief and this is one of the
pitiful prosthodontic error but unfortunately it occur frequently.

76. TEST FOR FACIAL NERVE
• The facial nerve is examined by testing the following facial muscles
Look for
horizontal
wrinkles
Showing
teeth
Tight closure of
eyes
Puffing mouth &
blowing forcibly as
in whistle

77. BELL’S PALSY
• Infranuclear lesion of the facial nerve, at the stylomastoid
foramen is known as bell’s palsy.
signs and symptoms of Bell’s palsy include:
• Upper & lower quarters on the same side gets paralyzed.
• Face becomes asymmetrical & drawn up to normal side.
• Wrinkles disappear on forehead.
• Attempt to smile draws mouth to normal side.
• Eyes cannot be closed, drooping eye.
• Drooping of corner of mouth.

78. REFERENCE
• Gray’s anatomy (thirty ninth edition)
• B D Chaurasia (sixth edition)