MUSCLES OF FACIAL EXPRESSION

BY: DR. NUZHAT NOOR AYESHAIyr MDS, KCDS

CONTENTS

INTRODUCTIONDEVELOPMENT OF FACIAL

MUSCLESCLASSIFICATION OF FACIAL

MUSCLESFACIAL MUSCLES IN DETAIL-

Origin, Insertion, Vascular Supply, Innervation & Action.

APPLIED ASPECTSREFERENCES

INTRODUCTION

FACIAL MUSCLES:

• No other animal have evolved as complex a set of facial muscles as have humans

• Morphologically, they represent remants of the Panniculus Carnosus, a continuous subcutaneous muscle sheet seen in some animals.

Characteristics of the facial musclesThe primary function is expression of the

emotions.The facial muscles are capable of performing

7000 expressions according to Coleman.They are also responsible for the maintenance

of the posture of the facial structures.The facial muscle also contributes to

stabilization of the mandible during the infantile swallowing and chewing and swallowing in the occlusally compromised adults.

It is also important for the visual and the spoken communications.

DEVELOPMENT OF FACIAL MUSCLES

EMBRYOLOGY• Each pharyngeal arch consists of mesenchymal

tissue, covered on outside by surface ectoderm and on inside by epithelium of endodermal origin.

• . The mesoderm of the arches give rise to musculature of face and neck.

Each arch is characterised by its own musculature and carry their own nerve

• The muscles of facial expression, the auricular muscles, stylohyoid, stapedius, posterior belly of digastric-originate from 2nd pharyngeal arch(hyoid arch).

• The facial nerve, the nerve of 2nd arch supplies all these muscles.

CLASSIFICATION

CLASSIFICATION OF ORO-FACIAL MUSCLES

Craniofacial Muscles

Epicranial muscles

Circumorbital and palpebral

Nasal

Buccolabial

CLASSIFICATION

CLASSIFICATION

CLASSIFICATION

CLASSIFICATION

FACIAL MUSCLES

MUSCLES OF FACIAL EXPRESSIONS

Epicranial muscle group

Occipitofrontalis Consists of 2 occipital and 2 frontal parts connected by epicranial aponeurosis

Origin

• Occipital part – lateral 2/3rd highest

nuchal line of occipital bone and

mastoid part of temporal bone.

• Frontal part – no bony attachments of its own , fibers blend

with adjacent muscles.

Insertion – into the epicranial aponeurosis.

Vascular supply

• Superficial temporal , Opthalmic ,Posterior auricular and

occipital arteries

Innervation

• Occipital part – posterior auricular branch of facial nerve

• Frontal part – temporal branch of facial nerve

Action

Frontal part

• Acting from above – raise the eyebrows

and skin over the root of the nose.

• Acting from below – draw the scalp

forward , throwing the forehead into

transverse wrinkles.

Occipital part – draws the scalp backwards

• Acting alternatively – move the entire

scalp backwards and forwards.

TEMPOROPARIETALIS

• Lies between the frontal parts of occipitofrontalis and anterior and superior auricular muscles.

Vascular supply

• Superficial temporal , Opthalmic ,Posterior

auricular and occipital arteries

Innervation

• Posterior auricular branch of facial nerve and

the temporal branch of facial nerve

CIRCUMORBITAL AND PALPEBRAL GROUP

Orbicularis oculi

• Has orbital ,palpebral and lacrimal parts.

Orbital part

Origin – nasal component

of frontal bone , frontal

process of maxilla and

medial palpebral

ligament.

Palpebral part – medial

palpebral ligament and

bone above and below

the ligament.

• Lacrimal part – upper part of lacrimal crest and adjacent lateral surface of lacrimal bone.

Insertion – skin around the margins of the orbit and tarsal plate.

Vascular supply – branches of facial , superficial temporal , maxillary , opthalmic arteries.

Innervation – temporal and zygomatic branches of facial nerve.

Action – closes eyelids

palpebral part- gently closes eyelids

orbital part- tightly closes them.

Corrugator supercilli

Origin- from bone at the medial end

of superciliary arch.

Insertion – skin above the middle of the supraorbital margin.

Vascular supply – superficial temporal , opthalmic arteries.

Innervation – temporal branch of facial nerve.

Action – with oculi muscle

shield the eye, involved in

frowning , vertical wrinkles

on the forehead.

FROWN

Procerus

Origin – facial aponeurosis covering lower

part of nasal bone and upper part of

lateral nasal cartilage.

Insertion – skin over lower part of

forehead between the eyebrows.

NASAL MUSCLE GROUP

Vascular supply – branches from facial artery.

Innervation – temporal and lower zygomatic branches of facial nerve.

Action – transverse wrinkles over the bridge of nose , help to reduce the glare of bright light.

• Consists of transverse and alar parts.

• Tranverse - from maxilla just lateral to

the nasal notch

• Alar part – from maxilla below and

medial to the transverse part

Insertion – nasal cartilages.

Nasalis

Vascular supply –infraorbital branch of

facial artery.

Innervation – buccal branch of facial

nerve.

Action

transverse- compresses the nasal

aperture.

alar -widening the anterior nasal

aperture.

-Deep inspiration

Depressor septi

Origin – maxilla above the central incisor

Insertion – mobile part of the nasal septum

Vascular supply – superior labial branch of facial artery

Innervation – buccal branch of facial nerve

Action – pulls the nasal septum downwards ,

with nasalis widens the nasal aperture.

Buccolabial group of muscles

• Elevators , retractors , evertors of upper lip

• Depressors, retractors, evertors of lower lip

• A compound sphincter – orbicularis oris ,

incisivus superior and inferior.

• Buccinator

Levator labii superioris alaequae nasi

Origin – upper part of the frontal process

of maxilla

Insertion – greater alar cartilage of nose

and skin over it , some fibers into

lateral part of upper lip and floor of

dermis at the nasolabial furrow and

ridge.

Vascular supply – facial artery and

infraorbital branch of maxillary artery.

Levator labii superioris alaequae nasi

Innervation – zygomatic and

buccal branches of facial

nerve.

Action – raises and everts the

upper lip, increases the

curvature of top of nasolabial

furrow , dilates the nostrils.

Levator labii superioris

Origin – maxilla and zygomatic

bone above the infraorbital

foramen.

Insertion– muscular substances of

upper lip

Vascular supply- facial artery and

infraorbital branch of maxillary

artery.

Levator labii superioris

Innervation . – zygomatic

and buccal branches of

facial nerve.

Action – elevates and everts

the upper lip, modifies the

nasolabial furrow.

Zygomatic major

Origin – zygomatic bone just in front of

zygomaticotemporal suture

Insertion – at the angle of the mouth

Vascular supply – superior labial branch

of facial artery

Zygomatic major

Innervation – zygomatic and buccal branches of facial nerve

Action – draws the angle of the

mouth upwards and laterally

as in laughing

LAUGH

Zygomatic minor

Origin – lateral surface of zygomatic

bone behind the

zygomaticomaxillary suture

Insertion – muscular substances of

upper lip

Vascular supply. – superior labial

branch of facial artery

Zygomatic minor

Innervation – zygomatic and buccal branches of

facial nerve

Action – elevates the upper lip, exposing the

max teeth , deepening and elevating

nasolabial furrow, curl the upper lip in smiling,

contempt.

Levator anguli oris

Innervation – zygomatic and buccal branches of facial nerve

Action – raises the angle of the mouth

In smiling, depth and contour of nasolabial furrow

Levator anguli oris

Origin – canine fossa of maxilla

Insertion – into and below the angle of

mouth

Vascular Supply – superior labial branch

of facial and infraorbital branch of

maxillary arteries

Mentalis

Origin – incisive fossa of mandibleInsertion – skin of the chin

Vascular supply - inferior labial branch of

facial and mental branch of maxillary

arteries

Mentalis

Innervation – mandibular branch

of facial nerve

Action – raises the lower lip ,

wrinkling the skin of the chin,

helps in drinking

Expression – doubt

Depressor labii inferioris

Origin – oblique line of the mandible between

the symphysis menti and mental foramen

Insertion – into the skin and mucosa of lower lip

Vascular supply – inferior labial branch of facial ,

mental branch of maxillary artery

Depressor labii inferioris

Innervation – mandibular

branch of facial nerve

Action – draws the lower lip

downwards and little laterally

and assist in eversion of lower

lip

Expression – irony , sorrow ,

doubt.

Depressor angular oris

Origin – mental tubercle of

mandible and its

continuation, the

oblique line –dep. labii inf.

Insertion – at the angle of the

mouth

Vascular supply – inferior labial branch of facial , mental branch of maxillary artery

Depressor angular oris

Innervation – buccal and

mandibular branches of

facial nerve

Action – draws the angle of

mouth downwards and

laterally in opening

mouth ,expressing sadness

sadness

Buccinator (whistling muscle)

Origin - upper fibers from outer surface of alveolar process of upper molar teeth , - lower fibers from

corresponding area of mandible ,

- middle fibers from pterygomandibular raphe

Buccinator (whistling muscle)

Insertion – upper fibers into upper lip ,

- lower fibers into lower lip ,

- upper of middle fibers cross the angle of mouth

to run into lower lip and lower of these fibers;

similarly run into upper lip

• Vascular supply – facial and buccal branch of maxillary arteries

• Action – compresses the cheek against the teeth and gums during mastication, and assist the tongue in directing food b/w the teeth

Innervation – buccal branch of facial nerve

Orbicularis oris

• Comprising of extrinsic and intrinsic parts.

Extrinsic part – consists of fibers of other muscles which converge on the lips

Intrinsic part – with in the lip consists 3 types of fibers – radiating , circular , antero - posterior

Orbicularis oris

Vascular supply – superior , inferior

labial branches of facial artery and

mental , infraorbital branches of

maxillary and transverse facial

branch of superficial temporal

artery

Innervation – buccal and mandibular

branches of facial nerve

Action – varying kind of movements

of lips like pouting , pursing ,

twisting

PURSING OF THE LIPS

Incisivus labii superioris

Origin – floor of incisive fossa of the maxilla

Insertion - modiolus

Incisivus labii inferioris

Origin - floor of incisive fossa of the mandible

Insertion - modiolus

Risorius (grinning muscle)

Origin – fascia covering the parotid

Insertion – skin, mucous membrane of angle of

mouth and orbicularis oris

Vascular supply – superior labial branch of facial

artery

Risorius (grinning muscle)

• Innervation – buccal branch of facial nerve

Action – pulls the corner of the mouth laterally

- grinning and laughing

GRINNING

Modiolus

• In facial anatomy, the modiolus is a chiasma of facial muscles held together by fibrous tissue, located lateral and slightly superior to each angle of the mouth. It is important in moving the mouth, facial expression and in dentistry. It derives its motor nerve supply from the facial nerve, and its blood supply from labial branches of the facial artery.

• It is contributed to by the following muscles: orbicularis oris, buccinator, levator anguli oris, depressor anguli oris, zygomaticus major, risorius quadratus labii superioris, quadratus labii inferioris.

Platysma

• Origin: upper parts of pectoral and deltoid fasciae. Fibres run upwards and medially.

• Insertion: anterior fibres, to the base of mandible; posterior fibres to the skin of the lower face and lip and may be continous with the risorius.

• Innervation: cervical branch of facial nerve

Action: releases pressure of skin on the subjacent veins; depresses mandible; pulls the angle of the mouth downwards as in horror or surprise.

APPLIED ASPECTS

Myotonia

• Failure of Muscle relaxation after the cessation of voluntary contraction

classified 3 types• Congenital• Acquired • Dystrophic

Dystrophic myotonia• Weakness of muscles

including of jaw , face, neck levators of eyelids.

• Ist occurs in hand, limb, arms

Ptosis of eyelids, atrophy of masseter and sternocleido mastoid, weakness of facial muscles.

‘Myopathic facies’ and ‘Swan neck’.

Myasthenia gravis• Auto immune disease

• Auto antibodies to acetyl choline receptors are seen

• Profound weakness of muscles

• diplopia , ptosis,drooping of face – sorrowful appearance of pt

• Dental interest- muscles of mastication and facial expression involved

Pt has difficulty in mastication and deglutition, slow slurred speech

Tr t- anticholinesterases are injected i/m

Drooping eyelids is an early and prominent sign.

“Sorrowful appearance”

• Facial soft-tissue injuries are not uncommon.The position and anatomy of the face make it particularly vulnerable to trauma

• a systematic approach to facial laceration repair ensures the best chance at an optimum outcome

FACIAL LACERATIONS

• Cosmetic results are better when minimal tension is placed on the wound edges at the time of repair. Therefore, wounds with the long axis parallel to the natural skin tension lines have much better cosmetic outcomes.

The degree of tension on the wound

edges can be estimated by measuring

the distance, the wound edges retract

away from the center of the lesion.

• Marked retraction (>5 mm) indicates

strong skin tension. With such wounds, placement of dermal sutures in a 2-layer closure should be considered.

Facial Hemiatrophy

• Characterised by progressive atrophy and wasting of subcutaneous fat, skin, cartilage, bone, muscle of essentially half of the face.

•Most common early sign is a painless cleft, ‘coup de sabre’ near midline of face/forehead.

•Bluish hue may appear in skin overlying atrophic fat.

Facial Hemihypertrophy

• Patients affected by condition exhibit an enlargement which is confined to one side of the body, unilateral macroglossia and premature development, and eruption as well as increased size of dentition.

• Cause is unknown, but has been variously ascribed to vascular or lymphatic abnormaliities; CNS disturbances; and chromosomal abnormalities.

HEMIFACIAL MICROSOMIA

• Syn-Goldenhar Syndrome, Brachial arch syn, Facio-auriculovertebral syn, lateral facial dysplasia.

• This condition in which tissues on

One side of face are underdeveloped

affecting primarily ear, mouth and

jaw areas.

• Sometimes both sides of face can be affected.

FACIAL PARALYSIS

Congenital MÖbius syndrome Myotonic dystrophy

FACIALPARALYSIS

Infectious/IdiopathicMelkerson-Rosenthal syndromeRamsay-HuntOtitis media/mastoiditis/meningitisLyme DiseaseNecrotizing Otitis externaHIV, TB, EBV, syphillisTetanus

SystemicSarcoidosisAmyloidosisHyperostosis

NeurologicGuillian-BarreMyasthenia GravisStrokeMultiple sclerosis

Toxins/TraumaHead traumaTemporal bone traumaBirth trauma

TumorParotidAcoustic neuromaGliomaMeningiomaFacial neuroma

REFERENCES

BD Chaurasia’s; Human Anatomy, 10th edition.

M Govindraj; Human Anatomy for BDS students, 1st edition.

Gray’s Anatomy; Anatomical basis of clinical practise, 39th edition

Grants; Atlas of Anatomy, 10th edition.

Text book of oral pathology-Shafer

A man's face is his autobiography -Oscar Wilde

THANK YOU