The document summarizes the mimetic muscles of the face, which are also called the facial expression muscles. It describes the various muscle groups - the orbicular group, nasal group, oral group, and others. It provides details on individual muscles like the orbicularis oculi, corrugator supercilii, zygomaticus major, and platysma. It also discusses the nerve supply of these muscles from the facial nerve and its branches.

3. Dr. Nasir Mustafa

19. Introduction-Mimetic Muscles
• The facial muscles are a group of striated
skeletal muscles innervated by the facial
nerve (cranial nerve VII) which control
facial expression. These muscles are also
called mimetic muscles.
• Facial Expressions- movements of mimetic
musculature of the face
19

20. • The facial musculature is fairly unique. They include
the only somatic muscles in the body attached on one
side to bone and the other to skin; thus facial
movements are specialized for expression.
• The face is also one of the few places in the body
where some muscles are not attached to any bone at
all (e.g., orbicularis oculi, the muscle surrounding the
eyes; orbicularis oris, the muscle in the lips).
• They also act as sphincters and dilators of the orifices
of the face
• Facial muscles develop from second pharyngeal arch.
20

21. Groups
• For logical understanding, they are grouped
as:
1. Orbicular Group
2. Nasal Group
3. Oral Group
4. Other muscles or groups
21

22. Orbicular Group
22

23. Orbicularis Oculi:
Closes and squints the eye.
Wink, concern, perplexion.
Levator Palpebrae Superioris:
Elevates the upper eyelid.
Surprise, fear
Corrugator Supercilii:
Draws the eyebrow
inferomedially and shows
anger, concern 23

24. Nasal Group
24

25. Nasalis:
Maxilla to the cartilage of the nose
and the oppositeside nasalis muscle.
Compresses the nares.
Procerus:
Fascia and skin medial to the
eyebrow to the fascia and skin over
the nasal bone (disdain look)
Depressor Septi Nasi:
From medial fiber of dilator naris muscle
to mobile part of nasal septum.
Depresses septum and narrows nostril 25

26. Oral Group
26

27. Levator labii superioris :
Infraorbital head & zygomatic head to
upper lip. Raises upper lip; helps form
naso -labial furrow. Disgust, smugness
Levator labiisuperioris alaeque nasi :
Frontal nasal process to one to ala &
other to orbicularis oris.Raises upper lip
and opens Nostril. anger, contempt
Levator anguli oris :
Maxilla below infraorbital foramen &
canine fossa to angle of mouth. Elevates
the angle of the mouth. smile, sneer,
“Dracula” expression 27

28. Zygomaticus major:
From zygomatic bone & arch to angle of
mouth. Draws the corner of the mouth
upward and laterally. Smile, laugh
Zygomaticus minor:
From zygomatic bone & medial to
zygomatic major to nasolabial groove.
Draws the upper lip upward. Smile &
Smugness.
Risorius:
From superficial fascia over parotid to
skin & mucosa on angle of lip. Retracts
corner of mouth. Grin, smile, laugh
28

29. Depressor anguli oris / triangularis:
From oblique line of mandible to angle
of mouth. Draws corner of mouth down
and laterally.
Depressor labii inferioris :
From base of mandible to skin n mucosa
of lower lip. Draws lower lip downward
and laterally. Sadness, uncertainty, dislike
Mentalis :
From mandible below lower incisors to
skin of chin. Raises and protrudes lower
lip as it wrinkles skin on chin. doubt,
pout, disdain 29

30. Orbicularis Oris:
From buccinator muscle to angle of
mouth (upper lip) and mandible
(lower lip). Closes lips; protrudes lips.
puckering, whistling
Buccinator :
From alveolar process f max. and mand. In
region of molars & pterygomandibular
ligament. Presses the cheek against teeth;
Compresses distended cheeks. pucker,
exertion, sigh
Platysma :
From skin and superficial fascia of pectoral
and deltoid region to lower border of
mandible. Draws up the skin of the superior
chest and neck. Creature from Black Lagoon”
expression 30

31. Other Group
31

32. Occipitofrontalis :
Frontal Belly:
From ant. Part of
Galea aponeurotica to
Skin on lower part
of forehead.
Wrinkles forehead;
Raises eyebrows
Anterior auricular: Draws ear
upward and forward
Occipital belly:
From lateral 2/3rd of
Superior nuchal line
To post. Part of
galea Aponeurotica.
Draws scalp
backward
Superior auricular : Elevates ear
Posterior Auricular: Draws ear
upward and backward
32
Cannot
consciously
move.
Temperoparietali
s has to be
checked.

33. Nerve Supply
33

34. Facial N. (VII)
• LMNs in facial nucleus is in inferior pons
• It emerges from the brainstem between the pons and the medulla, and
controls the muscles of facial expression
• The facial nerve is developmentally derived from the hyoid arch (second
pharyngeal branchial arch). The motor division of the facial nerve is
derived from the basal plate of the embryonic pons, while the sensory
division originates from the cranial neural crest.
Course:
• Fibres course around abducens nucleus - internal genu Exits
brainstem at cerebellopontine angle with CN VIII Through the
petrous part of the temporal bone Through internal acoustic meatus
with CN VIII Into facial canal, along walls of the tympanic cavity
(external genu of facial nerve, geniculate ganglion)
34

35. Exits skull via stylomastoid foramen, most branches go
through parotid gland
• Temporal
• Zygomatic
• Buccal
• Marginal mandibular
• Cervical
• Posterior auricular
• The oculomotor nerve [III], which innervates the
levator palpebrae superioris; sympathetic fibers,
which innervate the superior tarsal muscle.
35

36. 36

37.  The muscles of facial expression arise
from the second branchial arch,
 are innervated by the seventh cranial
nerve (i.e. the facial nerve, cranial
nerve VII),
 Fluidity of facial movements is
orchestrated by their interaction with
the SMAS

38.  The epicranius or occipitofrontalis muscle of the scalp
has an anterior and posterior region connected by the
galea aponeurotica . Contraction of these muscles
allows the skin to slide over the scalp.
 The frontalis muscle is a member of the epicranius
complex that begins at the anterior hairline and inserts
into the forehead and eyebrow skin.

39.  Midline vertical forehead skin tension
lines occur due to variation in distance
between the left and right frontalis bellies.
 Horizontal skin tension lines occur
perpendicular to the frontalis contractile
orientation.
 Loss of frontalis function results in
flattening of forehead skin tension lines
and a drooping eyebrow. This occurs when
the temporal branch of the facial nerve is
disrupted.
 Patients with compromised frontalis
function may be unable to open their eyes
widely, due to the synergistic effect this
muscle has with the orbicularis oculi
muscle.

40.  The small periauricular muscles or the
temporoparietalis group arise from the
superficial temporalis SMAS and the
lateral galea.
 They help draw back the temporal skin
and are innervated by the posterior
ramus of the temporal branch of the
facial nerve.

41.  The orbicularis oculi muscle
complex is the major group that
acts on the eyelid and periorbital
skin. It inserts into the medial
and lateral canthal tendons and
encircles the eye region.
 Its palpebral portion has a
preseptal component overlying
the orbital septum and a
pretarsal portion overlying the
tarsal plate of the eyelid. The
palpebral orbicularis oculi
muscle aids in tear excretion.
•Upper pretarsal and preseptal muscles depress the
upper lid. The orbital component of this muscle
group allows voluntary tight closure of the eye. The
palpebral portion allows gentle eye closure and
blinking.

42.  The corrugator supercilii muscle is located over the
medial upper orbital rim.
 It contributes to a 'scowling' facial expression by drawing
the eyebrows medially and downward.
 It interdigitates with and is covered by the frontalis and
orbicularis oculi muscles.
 The vertical and oblique skin tension lines of the
glabella are caused by contraction of this muscle, which
is innervated by the temporal branch of the facial nerve

43.  The procerus muscle
overlies the nasal bone
and attaches to the
nasal root skin.
 It causes
foreshortening of the
nose and 'rabbit lines‘
(i.e. skin tension lines
exaggerated by
wrinkling up the nose).

44.  The nasalis muscle courses
across the nasal dorsum and
facilitates alar 'flaring‘ and
compression. These muscles
are innervated by the
zygomatic and buccal
branches of the facial nerve.
 The depressor septi nasi
muscle lies deep to the
orbicularis oris and can form
a transverse skin tension line
across the philtrum. It plays
a minor role in facial
expression by pulling the
columella down toward the
lip

45.  The orbicularis oris muscle allows pursing and puckering
of the lips, apposition of the corners of the mouth, and
pulling of the lips up against the teeth and gingivae.
 It has no bony or cartilaginous attachment and is
innervated by the buccal or marginal mandibular branches
of the facial nerve.
 This circumferential muscle is necessary for correct speech
and allows enunciation of the letters M, V, F,P and O.
 The facial arteries and veins are covered and protected
from damage by the lip elevator muscles.

46.  The quadratus labii superioris muscle group is
comprised of several lip elevators.
 The levator anguli oris and risorius muscles
are mouth angle retractors and elevators.
 The zygomaticus major muscle travels from
the zygoma downward and diagonally to the
upper corner of the mouth, where it
contributes to the nasolabial fold.
 Zygomaticus major and minor muscles are the
main contributors to smile formation.
 The risorius muscle also contributes to a
smiling facial expression by drawing back the
corners of the mouth.
 The modiolus platform is formed by the
convergence of fibers from the orbicularis oris
and lip elevators and depressors.
 It is located 1cm lateral to the mouth angle
and accounts for cheek 'dimples' in some
patients. It works in synergy with the perioral
muscles to facilitate speech enunciation.

47.  The buccinator muscle constitutes a large area of the
cheek as it courses from the posterior maxillary area to
the upper medial surface of the mandible, where it
interdigitates with the orbicularis oris.
The buccinator is innervated by the
buccal branch of the facial nerve and
contracts synergistically with the
orbicularis oris muscle. Together, these
muscles allow whistling of the lips.
The buccinator also keeps the cheek flat
against the teeth, which prevents food
accumulation during chewing.
It also prevents overextension of the
cheek when high intraoral pressures are
generated.

48.  The depressor anguli oris (triangularis), depressor labii
inferioris (quadratus) and the mentalis muscles are lip
depressors and retractors that antagonize the superior
perioral muscle groups.
 They are innervated by the marginal mandibular branch of
the facial nerve.
 The deep mentalis muscle permits chin elevation and
depression and protrusion of the lower lip. The bellies of
the mentalis muscles have variable proximities to each
other.
 A patient with a chin 'dimple' or 'cleft chin‘ has a larger
distance between mentalis muscles. This is a normal anatomic
variant.

49.  The platysma muscle runs from
the superficial fascia of the chest
across the anterior and lateral
neck over the mandible to
intercalate with the lower lip
depressors and retractors.
 It is innervated by the cervical
branch of the facial nerve.