The Muscles Of Facial Expression

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    OF

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    GENERAL FEATURES OF THESE MUSCLES They are derivatives of the second branchial arches They are innervated by the Facial nerve (CN VII)

    except the Levator Palpebrae Superioris which is supplied

    by the Occulomotor Nerve N.B.injury to nerve leads to paralysis of facial muscles They are grouped mainly around natural openings of the

    skull: Orbit - Circumorbital & Palpebral,

    Nose - Nasal, Mouth - Buccolabial, Ear - Auricular (Exception: Epicranius)

    Only one end of facial muscles has bony attachment(s) The second end is attached to the skin and during

    muscular contraction it pulls the skin changing facialexpression They tend to pull open wounds of the face, which then

    require to be stitched Oral sphincter - Orbicularis oris has no direct

    attachments to bones. Indirect attachment is via LabialTractors

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    Muscles of Facial ExpressionEpicranius : Occipitofrontalis, Temporoparietalis ;Circumorbital & Palpebral : Corrugator supercilii;Orbicularis Oculi (Orbital, Palpebral & Lacrimal parts)Nasal : (Procerus, Nasalis, Depressor Septi);Buccolabial: Levator labii superioris alaeque nasi,Levator labii superioris, Incisivus labii superioris,Levator angulus oris, Zygomaticus Major, ZygomaticusMinor, Risorius, Mentalis, Depressor labii inferioris,Incisivus labii inferioris, Depressor anguli oris,Buccinator, Platysma (Mandibular, Labial & Modiolarparts)

    Oral Sphincter: Orbicularis OrisPars PeripheralisPars Marginalis

    Auricular : Auricularis anterior, superior & posterior

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    Muscles of Facial Expression Frontal View

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    Muscles of Facial Expression Lateral View

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    Circumorbital & Palpebral Muscles

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    Orbicularis OculiOrbital part:

    Muscle fibres are attached to the skin of eyebrow & overorbital margin

    It forcibly closes the eye as in protecting it from a blow & screws it up to give partial protection from bright lightIt arises from medial palpebral ligament & adjacent part of orbital margin of frontal bone & frontal process of maxillaIt forms complete loop on & around orbital margin & lateralcantus

    Palpebral part:It arises from medial palpebral ligament & adjacent part of orbital marginIt forms similar loop across eyelids & attached to their skinIt lightly closes the eye as in sleep or blinking

    Lacrimal part:It arises from upper part of posterior lacrimal crest & adjacent surface of lacrimal bone, from fascia of lacrimal sacIt gives upper & lower slips, which are attached to the tarsinear lacrimal canaliculi and to medial palpebral ligamentIt draws eyelids medially, dilates lacrimal sac & promotes

    flow of tear through itParalysis of muscle prevents the eye from being closed & permits

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    It consists of four quadrants: two right (upper & lower) & twoleft (upper & lower)

    Each quadrant consists of two parts:A larger part pars peripheralisA smaller part pars marginalis

    There is some interlacing and transmedian overlap of corresponding right & left quadrants

    Fibres of upper and lower quadrants converge laterally andhave modiolar attachment They receive slips of incisive muscles

    Muscle fibres are attached to labial connective tissue,submucosa, dermis & red lip dermisMuscle fibres of labial tractors pass perpendicular to andbetween circular fibres to be attached to labial submucosa,dermis & red lip dermisParalysis of one half of orbicularis oris prevents proper closerand movements of lips on affected side. Speech is slurred & food & fluids collect in oral vestibule & escape between lips.Lips are pulled toward normal side by unbalanced action of muscles of that side & cheek & lips are blownout and allow airto escape on paralysed side when patient blows against

    Orbicularis Oris Sphincter of Mouth

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    Lips, Orbicularis Oris its Quadrants & Parts

    Cupids bow

    Philtrum

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    Epicranius: Frontalis and Occipitalis - Eyebrows and scalpCongrugator Supercilli- EyebrowOrbicularis Oculi- Close EyeLevator Palpebrae Superioris- Upper Eyelid Zygomaticus major- Smiling

    Zygomaticus minor- SmilingLaevator Labii superioris- Upper LipLaevator Labii superioris alaeque nasi- Upper LipDepressor Labii Inferioris- Lower LipOrbicularis oris- Closes lips

    Depressor Anguli Oris- FrowningPlatysma- Frowning (during fear or shock)Nasalis- Flare NostrilsBuccinator- CheeksMentalis- ChinRisorius- Angle of the Mouth

    Summary of Actions of Muscles of FacialExpression

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    Summary of Actions of Muscles of Facial Expression

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    Vessels of Lips and Cheeks

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    THANK YOU