FACE

FACE Introduction• The face is the anterior aspect of the head from the forehead to the

chin and from one ear to the otherMuscles of facial expression• They are subcutaneousThey are grouped under the following six heads1. Muscles of the scalp Occipitofrontalis: is a flat diagastric muscle with two

bellies(frontal and occipital bellies) which share a common tendon called the epicranial aponeuroses

2. Muscles of the Auricle Aurcularis anterior Aurcularis superior Aurcularis posterior

3. Muscles of the eyelids Orbicularis oculi Corrugator supercilli Levator palpebrae superioris4. Muscles of the nose Procerus Tranverse part of nasalis muscle/ compressor naris Alar part of nasalis muscle/ dilator naris Depressor septi5. Muscles surrounding the mouth orbicularis oris Zygomaticus major Zygomaticus minor Levator labii superioris alaeque

Levator labii superioris Levator anguli oris Depressor anguli oris Depressor labii inferioris Mentalis Risorius Buccinator6. Muscles of the neck platysma

Functional groups of facial muscles

OPENING

A} Palpebral fissure

SPHINCTER

Orbicularis oculi

DILATORS

1. Levator palpebral superioris

2. frontalis part of occipitofrontalis

B} Oral fissure Orbicularis oris All the muscles around the mouth, except the orbicularis oris and the mentalis muscles

C} Nostrils Compressor naris/ tranverse part of nasalis muscle

1. Dilator naris/ alar part of nasalis muscle

2. Depressor septi3. Levator labii superioris

alaeque nasi

Common facial expression and the muscles producing them• Surprise : frontalis• Smiling and laughing : zygomaticus major• Sadness : levator labii suprioris, levator anguli oris, depressor

labii superioris, depressor anguli oris• Frowning: corrugator supercili and procerus• Anger: dilator naris (alar part of nasilis), depressor septi• Doubt: mentalis• Grinning: risorius• Closing of the mouth: orbicularis oris• Whistling: buccinator, and orbicularis oris• Tension and stress: platysma

Muscle FunctionOrbital group

Orbicularis oculi

Closes the eyelids gently

-Palpebral part        

-Orbital part Closes the eyelids forcefully

Corrugator supercilii

Draws the eyebrows medially and downward

Nasal groupNasalis-Transverse part

Compresses nasal aperture

-Alar part Draws cartilage downward and laterally opening nostril

Procerus Draws down medial angle of eyebrows producing transverse wrinkles over bridge of nose

Depressor septi Pulls nose inferiorly

Oral groupDepressor anguli oris

Draws corner of mouth down and laterally

Depressor labii inferioris

Draws lower lip downward and laterally

Mentalis Raises and protrudes lower lip as it wrinkles skin on chin

Risorius Retracts corner of mouth, grining

Zygomaticus major

Draws the corner of the mouth upward and laterally

Zygomaticus minor

Draws the upper lip upward

Levator labii superioris

Raises upper lip; helps formnasolabial furrow

Levator labiisuperioris alaeque nasi

Raises upper lip and opens nostril

Levator anguli oris

Raises corner of mouth; helps form nasolabial furrow

Orbicularis oris Closes lips; protrudes lips, osculation (kissing)

Buccinator Presses the cheek against teeth; compresses distended cheeks, whistling

Other muscles or groups

Anterior auricular

Draws ear upward and forward

Superior auricular

Elevates ear

Posterior auricular

Draws ear upward and backward

Occipitofrontalis-Frontal belly

Protracts scalp, Wrinkles forehead; raises eyebrows

-Occipital belly Draws scalp backward

Nerves of the faceThese include:1. Cutaneous(sensory) innervation of the face is provided

primarily by the trigeminal nerve (CN V)2. Motor innervation to the face is from the facial nerve (CN

VII)Cutaneous nerves of the face Trigeminal nerve ( main contribution) A small contribution from the cervical nerves The trigeminal nerve [V] divides into 3 major divisions namely:• ophthalmic nerve[V1] exit through the supraorbital fissure• maxillary nerve [V2] exit through the foramen rotundum• mandibular nerve[V3] exit through the foramen ovale

• they are named according to their main areas of their termination Eye…………………..ophthalmic divison maxilla……………….Maxillary division mandible……………..mandibular division

Ophthalmic nerve (CN V1)• superior division of the trigeminal nerve• smallest of the three divisions of CN V• Arises from the trigeminal ganglion as a wholly sensory nerve• The ophthalmic nerve [V1] exits the skull through the superior orbital

fissure and enters the orbitBranches Its branches that innervate the face include:• supratrochlear nerve which leaves the orbit superiorly and supplies the

upper eyelid and forehead• supraorbital nerve which leaves the orbit superiorly and supplies the

upper eyelid, forehead and scalp

• infratrochlear nerve: exits the orbit in the medial angle to innervate the medial parts of both eyelids

• lacrimal nerve: exits the orbit in the lateral angle to innervate the lacrimal gland and the lateral part of the upper eyelid

• external nasal nerve: supplies the anterior part of the noseMaxillary nerve (CNV2)• is the intermediate division of the trigeminal nerve• arises from the trigeminal ganglion as a wholly sensory nerve• leaves the cranium through the foramen rotundum in the base of the

greater wing of the sphenoid • it enters the orbit through the inferior orbital fissure of the maxillaBranches:Branches that innervate the face include:• a small zygomaticotemporal branch, which exits the

zygomaticotemporal foramen on the zygomatic bone and supplies the anterior part of the temporal fossa

• a small zygomaticofacial branch, which exits the zygomaticfacial foramen on the zygomatic bone and supplies the skin on the upper part of the cheek

• the large infra-orbital nerve, which exits the maxilla through the infra-orbital foramen and immediately divides into multiple branches to supply the lower eyelid, side of the nose, and upper lip

Mandibular nerve• the inferior and largest division of the trigeminal nerve• formed by the union of sensory fibers from the sensory ganglion

and the motor root of CN V in the foramen ovale in the greater wing of the sphenoid

• CN V3 has 3 sensory branches that supply the face• It also supplies motor fibers to the muscles of mastication Note: CN V3 is the only division of CN V that carries motor fibers

Branches: 3 major cutaneous branches that supply the face are; Auricotemporal nerve: supplies the external acoustic meatus,

temporal region Buccal nerve: skin of the lower part of the cheek mental nerve: skin over chin

Cervical plexus branches that supply that face:• Anterior division of great auricular nerve : supply skin over the

mandible and over the parotid gland

Clinical anatomyLesions of the Trigeminal Nerve

Can affect;• Corresponding anterior half of the scalp• Face, except for an area around the angle of the

mandible, the cornea, and conjunctiva• Mucous membranes of the nose, mouth, and anterior

part of the tongue• Paralysis of the muscles of mastication also occurs

Motor innervation to the Face The motor nerves of the face are;• the facial nerve to the muscles of facial expression • the motor root of the mandibular division of the trigerminal nerve

(CNV3) to the muscles of mastication which are; masseter temporal Medial pterygoid lateral pterygoid

Facial nerve (CN VII) • The motor root of CN VII supplies the muscles of facial expression, • The main trunk of CN VII which runs anteriorly is engulfed by the

parotid gland, in which it forms the parotid plexus

It gives rise to the 5 terminal branches of the facial nerve:1. temporal2. Zygomatic3. buccal4. marginal mandibular5. cervicalThe names of the branches refer to the regions they supply Temporal branch of CNVII :• emerges from the superior border of the parotid gland and crosses

the zygomatic arch to supply the; • auricularis superior • auricularis anterior• frontal belly of the occipitofrontalis• and,most important, the superior part of the orbicularis oculi

Zygomatic branch of CNVII: emerge from the anterosuperior border of the parotid gland to supply the;

• inferior part of the orbicularis oculi (supra orbital area), lateral part of the nose and upper lip

Buccal branch of CN VII: emerge from the anterior border of the parotid gland to supply the;

• muscles of the upper lip (upper parts of orbicularis oris and inferior fibers of levator labii superioris)

marginal mandibular branch of CN VII: emerge from the anterior inferior border of the parotid gland to supply the;

• risorius • muscles of the lower lip and chin Cervical branch of CN VII: emerge from the inferior border

of the parotid gland to supply the;• platysma

CLINICAL ANATOMY• Injury to branches of the facial nerve causes

paralysis of the facial muscles (Bell palsy)• A lesion of the zygomatic branch of CN VII causes

paralysis, including loss of tonus of the orbicularis oculi in the inferior eyelid

• Paralysis of the buccal branch of CN VII causes paralysis of the buccinator and superior portion of the orbicularis oris and upper lip muscles

• Paralysis of the marginal mandibular branch of CN VII causes paralysis of the inferior portion of the orbicularis oris and lower lip muscles

Note: Because the branches of the facial nerve are superficial, they are subject to injury by stab and gunshot wounds, cuts, and injury at birth