MUSCLES OF FACIAL EXPRESSIONMUSCLES OF FACIAL EXPRESSION Dr. VIJAY 1st yr PG

Introduction Facial expression results from one or more

motions or positions of the muscles of the face.

These movements convey the emotional state of the individual to the observer.

Facial expressions are a form of non verbal communication.

Humans can adopt facial expression as voluntary action. However, as facial expressions are relative to emotional state, more often they are involuntary

The motor supply to these muscles is by the Facial nerve & the sensory supply is from the Trigeminal nerve

EMBRYLOGICALLY, they develop from the mesoderm of the second branchial arch , therefore, supplied by 7TH CN.

Classification of Facial muscles

Topographically, the muscles are grouped under the following six heads.

Muscles of the scalp Occipitofrontalis Muscles of the auricle, situated around the

ear Auricularis anterior Auricularis superior Auricularis posterior

Muscles of eyelids Orbicularis oculi Corrugator supercilli Levator palpabrae superioris Muscles of nose Procerus Compressor naris Dilator naris Depressor naris Depressor septi

Muscles around the mouth Orbicularis oris Levator labii superioris alaequae nasi Zygomaticus major Zygomaticus minor Levator labii superioris Levator anguli oris Depressor anguli oris Depressor labii inferioris Mentalis Risorius Buccinator Muscles of neck Platysma

Anatomy of muscles of facial expression

Occipitofrontalis It covers the dome of the skull from the highest

nuchal lines to the eyebrows. It’s broad musculofibrous layer consisting of four thin, muscular quadrilateral parts. Two occipital & two frontal parts are connected by epicranial aponeurosis.

Occipitalis Origin: Each occipital part (Occipitalis) arises by the

tendinous fibres from the lateral two-thirds of the highest nuchal lines of the occipital bone & adjacent region of the mastoid part of the temporal bone.

Attachment: Extends forward from the mastoid part of the temporal bone & gets attached to the aponeurosis.

Nerve innervations: posterior auricular branch of the facial nerve.

Action: The Occipitalis draw the scalp backwards. Acting alternatively with the frontalis part, they can move the entire scalp forwards & backwards

Frontalis Origin: arises from the skin of the forehead. Attachment: Frontalis has no bony attachment of

its own. Frontalis is adherent to the superficial fascia, particularly of the eyebrows. Fibres from the frontalis blend with the adjacent muscles –Procerus, Corrugator supercilli & Orbicularis occuli. Then it ascends to join the epicranial aponeurosis in front of the coronal suture.

Nerve innervations: supplied by the temporal branches of the facial nerve.

Vascular supply: Occipitofrontalis is supplied by the branches of the superficial temporal, ophthalmic, posterior auricular & occipital arteries.

Action: Acting from above the frontalis raises the eyebrows and the skin over the root of the nose. Acting from below, the frontalis draws the scalp forwards, throwing the forehead into transverse wrinkles.Facial expressions elicited: surprise & horror!

Muscles of the Auricle Auricularis anterior Auricularis superior Auricularis posterior

Auricularis anterior The Auricularis anterior is the smallest of the three

extrinsic muscles of the ear. It is a thin fan of fibres. Origin: Fibres of the Auricularis anterior arise from the

lateral edge of the epicranial aponeurosis. Insertion: The fibres of the muscle converge to insert into

the spine of the helix. Nerve innervations: supplied by the temporal branch of the

facial nerve. Action: In man these muscles have very little consequence

from their action. Auricularis anterior draws the ear forward & upward

Auricularis Superior

Origin: It is the largest of the three muscles. It converges from the epicranial aponeurosis via a thin flat tendon.Attachment: Auricularis superior attaches to the upper part of the cranial surface of the auricle. Nerve innervations: supplied by the temporal branches of the facial nerveAction: Auricularis superior elevates the auricles slightly

Auricularis Posterior

Origin: Auricularis posterior consist of two or three fleshy fascicule which arise by short aponeurotic fibres from the mastoid part of the temporal bone.

Insertion: Insert into the ponticulus on the eminentia conchae. Vascular supply: The arterial supply of the extrinsic auricular

muscles is derived mainly from the posterior auricular artery. Nerve innervations: Auricularis posterior is supplied by the

posterior auricular branch of the facial nerve. Action: Auricularis posterior draws the auricles back.

Muscles of eyelids Orbicularis oculi Corrugator supercilli Levator palpabrae superioris

Orbicularis oculi

Orbicularis occuli is a broad, flat, elliptical muscle that surrounds the circumference of the orbit & spreads into the adjacent regions of the eyelids. It has orbital, palpebral & lacrimal parts. The Orbicularis oculi is a muscle in the face that closes the eyelids.

Origin: frontal & maxillary bones

Insertion: tissue of eyelid

Action: The Orbicularis oculi is the sphincter muscle of the eyelids. The palpebral portion acts involuntarily, closing the lids gently, as in sleep or in blinking.

Vascular supply: It is supplied by the branches of facial, superficial temporal, maxillary & ophthalmic arteries.

 Nerve innervations: It is supplied by temporal & zygomatic branches of the facial nerve.

Corrugator supercilli

The Corrugator supercilii is a small, narrow, pyramidal muscle, placed at the medial end of the eyebrow, beneath the Frontalis and Orbicularis oculi.

Origin: It arises from the medial end of the superciliary arch

Insertion: Corrugator supercilii inserted into the deep surface of the skin, above the middle of the orbital arch

Nerve innervations: Corrugator supercilii is innervated by the temporal branches of the facial nerve.

Vascular supply: Corrugator supercilii is supplied by the adjacent arteries, mainly from the superficial temporal & ophthalmic arteries.

Action: The Corrugator draws the eyebrow downward and medial ward, producing the vertical wrinkles of the forehead.

It is the “frowning” muscle, and may be regarded as the principal muscle in the expression of suffering.

Levator palpebrae superioris

Origin: the lesser wing of the sphenoid bone, just above the optic foramen.

Insertion: This portion inserts on the skin of the upper eyelid, as well as the superior tarsal plate

Nerve innervations: the oculomotor nerve (Cranial Nerve III).

Action: The levator palpebrae superioris muscle elevates and retracts the upper eyelid

Muscles of nose Procerus Nasalis

a. Compressor naris

b. Dilator naris

c. Depressor septi

Procerus

Procerus is a small pyramidal slip close to, & often partially blended with, the medial side of the frontal part of the Occipitofrontalis.

Origin: It arises by tendinous fibers from the fascia covering the lower part of the nasal bone and upper part of the lateral nasal cartilage.

Insertion: It is inserted into the skin over the lower part of the forehead between the two eyebrows

Nerve innervations: supplied by temporal & lower zygomatic branches of the facial nerve.

Vascular supply: Procerus is mainly supplied by the branches of the facial artery.

Action: It helps to pull that part of the skin between the eyebrows downwards, which assists in flaring the nostrils. It can also contribute to an expression of anger.

Nasalis

Nasalis consist of transverse & alar parts Origin: The Transverse part (compressor naris)

arises from the maxilla just lateral to the nasal notch. The alar part (dilator naris) arises from the maxilla from below & medial to the transverse part.

Insertion: The fibres of the transverse part pass upward & medially & expand into the thin aponeurosis. At the bridge of the nose the paired compressor naris muscle merge with each other and aponeuroses of the Procerus. The dilator naris partly merges with the transverse part & is attached to the cartilaginous ala nasi.

Vascular supply: Nasalis is supplied from the branches of the facial artery & the infraorbital branch of the maxillary artery.

Nerve innervations: Nasalis is supplied by the buccal branch of the facial nerve & also contribution from the zygomatic branch.

Action: Compressor Nasalis compresses the nasal aperture at the junction of the vestibule of the nose with the nasal cavity. The dilator nasalis draws the ala downwards & laterally so as to facilitate the widening of the anterior nasal aperture. These actions are associated with deep inspiration, & are thus associated with exertion & also with some emotional states.

Buccolabial group of muscles (muscles around the mouth)

The shape of the mouth & the posture of the lips are controlled by complex three dimensional assemblies of muscular slips. These include elevators, retractors & evertors of the upper lip(levator labii superioris alaequae nasi, levator labii superioris, Zygomaticus minor & major, levator anguli oris & Risorius) ; depressors ,retractors & evertors of the lower lip(depressor labii inferioris, depressor anguli oris & Mentalis); a compound sphincter(Orbicularis oris, incisivus superior & inferior); Buccinator.

Levator labii superioris alaeque nasi

Origin: It arises from the upper part of the frontal process of the maxilla & divides into medial & lateral slips.

Insertion: The medial slip is inserted into the greater alar cartilage of the nose & the skin over it. The lateral slip is prolonged into the lateral part of the upper lip

Vascular supply: supplied by the facial artery & the infra orbital branch of the maxillary artery.

Nerve innervations: zygomatic & the buccal branches of the facial nerve.

Action: The lateral slip raises & everts the upper lip. The medial slip dilates the nostril

Levator labii superioris

Origin: The levator labii superioris (or quadratus labii superioris) is a broad sheet of muscle. It arises from the maxilla & zygomatic bone above the infra orbital foramen.

Insertion: Its fibres converge into the muscular substance of the upper lip between the lateral slip of the levator labii superioris alaequae nasi & the Zygomaticus minor.

Vascular supply: It’s supplied by the facial artery & the infraorbital branch of the maxillary artery

Nerve Innervations: It’s innervated by the zygomatic & buccal branches of the facial nerve.

Action: It elevates & everts the upper lip,

expressions of sadness or seriousness

Zygomaticus major

The Zygomaticus extends from each zygomatic arch (cheekbone) to the corners of the mouth.

Origin: the zygomatic bone, Insertion: the angle of the mouth Vascular supply: superior labial

branch of the facial artery. Nerve innervations: the

zygomatic & buccal branch of the facial nerve.

Action: It draws the angle of the mouth upwards & laterally in laughing.

Zygomaticus minor

Origin: lateral surface of the zygomatic bone immediately behind the zygomaticomaxillary suture.

Insertion: It passes downwards & medially into the muscular substance of the upper lip.

Vascular supply: It’s supplied by the superior labial branch of the facial artery.

Nerve innervations: Zygomaticus minor is innervated by the zygomatic & the buccal branch of the facial nerve.

Action: Elevates the upper lip, exposing the maxillary teeth. Acting together, the main elevators of the lip- levator labii superioris alaequae nasi, levator labii superioris & Zygomaticus minor – curl the upper lip in smiling, & in expressions of smugness, contempt or disdain

Levator anguli oris

Origin: Arises from the canine fossa of the maxilla, below the infraorbital foramen.

Insertion: It inserts into & below the angle of the mouth.

Vascular supply: It is supplied by the superior labial branch of the facial artery & the infraorbital branch of the maxillary artery.

Nerve innervations: It is innervated by the zygomatic & buccal branches of the facial nerve.

Action: It raises the angle of the mouth in smiling

Origin: It is a conical fasciculus lying at the side of the frenulum of the lower lip.

Insertion: The fibres descend from the incisive fossa of the mandible & attach to the skin of the chin.

Vascular supply: the inferior labial branch of the facial artery & the mental branch of the maxillary artery.

Nerve Innervations: It is innervated by the mental branch of the facial nerve.

Depressor anguli oris

Origin: It has a long linear origin from the mental tubercle of the mandible

Insertion: insertion with the Orbicularis oris and Risorius; some of its fibers are directly continuous with those of the Caninus

Vascular supply: It is supplied by the inferior labial branch of the facial artery & the mental branch of the maxillary artery.

Nerve Innervations: It is innervated by the buccal & mandibular branches of the facial nerve.

Action: It draws the angle of the mouth downwards & laterally in opening the mouth & in expression of sadness

Buccinator

Origin: Upper fibres ,from maxilla opposite molar teeth Lower fibres, from mandible opposite to molar teeth Middle fibres, from pterygomandibular raphe Insertion: Upper fibres, straight to upper lip Lower fibres, straight to lower lip Middle fibres, decussate before passing to the lips

Vascular supply: It is supplied by the branches of the facial artery & the buccal branches of the maxillary artery.

Nerve innervations: Buccinator is supplied by the buccal branch of the facial nerve.

Action:flattens the cheek against the gums and teeth during mastication, & prevents accumulation of food in the vestibules. Whistling muscle.

Orbicularis oris

The Orbicularis oris is not a simple sphincter muscle like the Orbicularis oculi; it consists of numerous strata of muscular fibers surrounding the orifice of the mouth but having different direction.

intrinsic part - O : superior incisivus,from maxilla; inferior incisivus, from mandible , I : angle of mouth

Extrinsic part – O : thickest middle stratum, derived from buccinator; thick superficial stratum, derived from elevators and depressors of lips and their angles, I : lips and the angle of the mouth

Clinical significance Newborn babies are occasionally born without

one or both sides of this particular muscle resulting in a slight droop to the affected side of the face

Vascular supply: It is mainly supplied by the superior & inferior labial branches of the facial artery, the mental & infra orbital branches of the maxillary artery & the transverse facial branch of the superficial temporal artery.

Nerve supply: It is supplied by the buccal & mandibular branches of the facial nerve.

Action: closes & purses the mouth; numerous extrinsic muscles make it most versatile for various types of grimaces.

Muscles of neck Platysma

Origin: upper part of pectoral and deltoid fasciae, fibres run upwards and medially

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

Vascular supply: The Platysma is supplied by the cervical branch of the facial artery.

Nerve innervations: It is supplied by the cervical branch of the facial nerve.

Action: When the entire Platysma is in action it produces a slight wrinkling of the surface of the skin of the neck in an oblique direction. Its anterior portion, the thickest part of the muscle, depresses the lower jaw; it also serves to draw down the lower lip and angle of the mouth in the expression of horror or surprise.

Smiling & Laughing: Zygomatics Major Sadness: Levator Labii Superioris and Levator

Anguli Oris Grief: Depressor Anguli Oris Anger: Dilator Naris & Depressor Septi Frowning: Corrugator Supercilii & Procerus Horror, Terror & Fight: Platysma Surprise: Frontalis Doubt: Mentalis Grinning: Risorius Contempt: Zygomatic Minor Closing of mouth: orbicularis oris Whistling: buccinator and orbicularis oris

Facial nerve palsy

Bell’s palsy Whole face of same side gets paralysed. Face becomes asymmetrical and drawn up to normal

side. Motionless – affected side Wrinkles disappear from forehead Eye can not be closed Drooping of mouth Drooling of saliva Food accumulates b/w teeth and cheek. Not able to blow.

Usually part of hemiplegia,

Only lower part of opposite side of face is paralysed.

The upper part with frontalis and orbicularis oculi escapes due to its bilateral representation in the cerebral cortex.

Mobius syndrome results from the underdevelopment of the VI and VII cranial nerves

extremely rare congenital neurological disorder which is characterized by facial paralysis and the inability to move the eyes from side to side.

Often, the upper lip is retracted due to muscle shrinkage

Most people with Mobius syndrome are born with complete facial paralysis and cannot close their eyes or form facial expressions.

People with Mobius syndrome have normal intelligence, although their lack of facial expression is sometimes incorrectly taken to be due to dullness or unfriendliness

Children with Mobius syndrome may have delayed speech because of paralysis of muscles that move the lips, soft palate, and tongue root.

Ramsay Hunt syndrome (also termed Hunt's Syndrome and herpes zoster oticus) is a herpes zoster virus infection of the geniculate ganglion of the facial nerve. It is caused by reactivation of herpes zoster virus that has previously caused chickenpox in the patient. Ramsay Hunt syndrome results in paralysis of the facial muscles on the same side of the face as the infection. So, the virus infects the facial nerve that normally innervates controls the muscles of the face. Ramsay Hunt syndrome is typically associated with a red rash and blisters (inflamed vesicles or tiny water-filled sacks in the skin) in or around the ear and eardrum and sometimes on the roof of the mouth or tongue.

If any injury to the nerve which supplies that muscle, it will lead to paralyses of that muscle. This causes the dropping of lower eyelid , called as “Ectropion’’ and

Spilling of tears , called as “Epiphora”.

Some times there will be radiating wrinkles at the angle of the eye during strong closure. This called as “Crow’s Feet”

Risorisus Sardonicus: Smile in tetanus It is the smile like feature in agony due to

pulling of the muscles of the angle