muscles of facial expressions
DESCRIPTION
Muscles of facial expressionsTRANSCRIPT
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
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