FACIAL MUSCLES

By, velavan.k

Dept of OMFS

• The muscles of facial expression are subcutaneous.

• They move the skin and change facial expression to convey mood.

• They develop from the mesoderm of the second brachial arch ,and therefore supplied by the facial nerve.

• Most muscles attach to bone or fascia and produce their effects by pulling the skin.

INTRODUCTION

CLASSSIFICATIONTOPOGRAPHICALLY• The muscles are grouped under following six heads scalp 1. Occipito frontalis - auricle(around the ear) 1. Auricularis anterior 2. Auricularis posterior 3. Auricularis superior - eyelid 1. Orbicularis oculi 2. Corrugator supercilii 3. Levator palpebrae superioris(extra

ocular muscle, supplied by III cranial nerve)

- nose 1. Procerus 2. Compressor naris 3. Dilator naris 4. Depressor septi - mouth 1.Orbicularis oris 2. Levator labii superioris alaequae nasi 3. Levator labii superioris 4. Zygomaticus major 5. Zygomaticus minor 6. Depressor anguli oris 7. Depressor labiii inferioris

9. Mentalis 10. Risorius 11.Buccinator

- neck 1. Platysma.

FUNCTIONALLY • these are primarily regulators of 3 openings

palpebral fissures,nostrils ,oral fissure.• Each opening has single sphincter & a variable

no. of dilators.• Sphincters – circular , dilators – radial in their

arrangement.

Functional group of facial muscles

Opening Sphincter dilator

a.Palpebral fissure

b.oral fissure

c. Nostrils

Orbicularis oculi

Orbicularis oris

Compressor naris

1. Levator labii superioris 2. Occipito frontalis

All the muscles except the orbicularis oris & the mentalis.

1. Dilator naris2. Depressor septi3. Medial slip of lev.labi. Alaque nasi.

• Common facial expressions : 1. smiling & laughing –zygomaticus major 2. sadness – levator labii superioris, levator angulioris 3. grief – depressor anguli oris 4. anger – dilator naris & depressor septii 5. frowning –corrugator supercilii & procerus 6. horror, terror& fright – platysma 7. surprise – frontalis 8. doubt – mentalis 9. grinning – risorius 10. contempt – zygomaticus minor

EXAMINATION:1. Frontalis – ask the pat to look upwards ,without

moving the head,look for horizontal wrinkles.2. Corrugator supercilli - frowning & making vertical

wrinkles.3. Orbicularis oculi- tight closure of eyes.4. Orbicularis oris – whistling & pursing the mouth.5. Dilators of the mouth – showing the teeth.6. Buccinator – puffing the mouth & then blowing

forcibly.7. Platysma - forcible pulling of the angles of the

mouth downwards forming prominent vertical folds of skin on the side of the neck . It contracts along with risorius.

ORIGIN & INSERTION

-Occipitofrontalis muscle-frontal belly arises from anterior part of the epicranial aponeurosis .

-it has no bony attachments .

-it elevates the eyebrows, gives a surprised look,and produce transerve wrinkles in the forehead when one frowns

FRONTALIS

CORRUGATOR SUPERCILII origin – medial end of superciliary arch insertion – skin of mid eye action – vertical wrinkling of forehead ,frowning

ORBICULARIS OCULIa. orbital part –on & around the marginal

margin , origin – medial part of medial palpebral ligament &adjoining bone.

insertion – concentric rings return to the point of origin.

action – closes lids tightly ,winking ,protects eye from bright light.

b. palpebral part ;-lateral part of medial palpabral ligment ins –lateral palpebral raphe

act – closes lip gently & blinkingC . Lacrimal part - lacrimal fascia & bone ins - upper & lower tarsi act – dilates lacrimal sac

3.ORBICULARIS ORISa) Intrinsic part – superior incisivus- maxilla inf incisivus from mandible ins – angle of mouth act – closes and purses

mouth

b) Extrinsic part – two strata formed by

converging muscles, thickest middle stratum by buccinator

ins – lip & angle of the mouth

• DILATORSLEVATOR LABII

SUPERIORIS ALAEQUE NASI

-elevator of upper lip & wings of nose .

- Attaches superiorly to the maxilla .

- Divides into two slip – attach to alar cartilage ; another to upper lip.and elevates the both.

• MENTALIS - incisive fossa of

mandible . - ins – skin of chin Act - elevates &

protrudes lower lip.

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4. BUCCINATOR (MUSCLE OF THE CHEEK)

a) upper fibres from maxilla ,ins – straight into upper lip

b) lower fibres from mandible ,ins – straight to lower lip c) middle – pterygomandibular raphe ,ins – decussate before passing to the lips.

Action – Flattens cheek against gums and teeth.

• DEPRESSOR ANGULI ORIS

- depresses the angle of the mouth.

- during frowning. - posterior fibers of

platysma assist with this movement.

• LEVATOR ANGULI ORIS

- attaches superiorly to the infraorbital margin & inferiorly to the angle of mouth.

- elevates the corner of mouth.

• ZYGOMATICUS MAJOR

- extends from zygomatic bone to the angle of the mouth.

- draws the angle of mouth superolaterally

- Occurs during smiling / laughing.

• ZYGOMATICUS MINOR

- a narrow slip of muscle,passes obliquely from the zygomatic bone to the orbicularis oris .

- raise the upper lip when showing contempt .

- deepen the nasolabial when showing sadness.

• LEVATOR LABII SUPERIORIS

- descends infraorbital margin to upper lip.

- raises & elevates upper lip.

- also helps in sadness.

• DEPRESSOR LABII INFERIORIS

- Lat to mentalis, attaches inferiorly to the mandible.

- draws the lip inferiorly & slightly laterally , as showing impatience.

• RISORIUS - arises from platysma

& fascia of masseter. - attaches to fascia

covering the parotid gland inferoanterior to the ear & angle of the mouth laterally when grinning.

PLATYSMA• PLATYSMA –upper parts of

pectoral & deltoid fasciae .fibres run upwards and medially.

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

• Action-release pressure of skin on the subjacent veins ;depresses mandible;pulls the angle of the mouth downwards as in horror or surprise

• NASALIS - superior part of

canine ridge of maxilla.

- nasal cartilages. - draws ala of the nose

toward nasal septum.

• PROCERUS - Slip of muscle

continuous with frontalis .

- draws medial part of the eyebrow inferiorly ,producing transverse wrinkles over bridge of the nose .

- to reduce the glare of sunlight.

• DEPRESSOR SEPTI - Arises superior to

central incisor tooth. - inserts into the

mobile part of the nasal septum.

- assists the alar part of nasalis to widen the nostril during deep inspiration.

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