The Face Flashcards
how many different categories of emotion can we signal by selective contraction and relaxation of facial muscles
more than 20
how are human faces distinctly different from our nearest living relatives
face relatively small
cranium large
remainder of the skull is more vertical in profile
our faces are tucked under the anterior aspect of the brain case (apes = brain more posterior to their face)
how many bones make up the facial skeleton
14
what 4 systems does the complex of facial bones house parts of
digestive
respiratory
visual
olfactory (smell)
how are the soft tissues of the face arranged
series of layers (nature of these layers varies in different parts of the face)
what are soft tissue layers connected together and to the underlying facial skeleton by
retaining ligaments (bundles of fibrous connective tissue)
what happens to soft tissues of the face with age
begin to sag and so retaining ligaments cause lines / creases to develop
how do the movements of the soft tissue cause wrinkles
retaining ligaments retain og length (relatively unchanged)
tissues around them get saggy bulging around the retaining ligament
bc the retaining ligament doesnt change a crease develops where it is as soft tissue bulges out
so what do facial creases indicate
position of retaining ligaments which are holding the face onto the skull
what can the soft tissues of the face be considered as
a single unit structure (called a FLAP in surgical context)
what does the face being a single unit structure enable in surgical terms
face transplant operations
how does face transplant work
soft tissues removed as single piece (flap) and transplanted onto reconstructed facial skeleton of the recipient
what can the outcomes of face transplants be
v acceptable cosmetic result
patients gain movement (motor function) and sensation in new face
what are the general layers of soft tissue
1) skin (most superficial)
2) subcutaneous tissue - fatty connective tissues
3) layer consisting of muscles and fibrous connective tissue (most deep)
what is the layer containing muscles of facial expression mixed with fibrous connective tissue that covers the whole of the face called
superficial musculoaponeurotic system (SMAS)
what are muscle parts of the SMAS examples of
muscles of facial expression (series of interconnected muscles which are ALL in this layer)
what do we know about the components of the SMAS
exact nature of distribution is disputed
muscles it contains are well known
fibrous tissue in it is intertwined w and connects muscles of facial expression
as an anatomical structure what is the SMAS
controversial
some people think it doesnt exist but its a key concept in modern plastic surgery esp facelifts)
why is “aponeurotic” included in the SMAS
an aponeurosis = flat tendon of muscle
what are the muscles encircling the eyes called
obicularis oculi
what is the muscle of the cheek called and where does it run
the buccinator
in the cheek attaching to the maxilla superiorly and mandible inferiorly (more substantial than most muscles of facial expression)
what is the name for the muscles encircling the corners of the mouth and where do they insert into
oral commisures
the modiolus lateral to them
what is dramatic at the oral commissures and why
difficulty of telling where one muscle ends and next one starts because they tend to blend together
because just lateral to each commissure several muscles of facial expression blend together.
which muscle encircles the opening of / orbits the mouth and what does it act as
obicularis oris
a sphincter (of the mouth) - purses lips
what is the name for a hub region where many muscles of facial expression merge together and WHY
where is this found
modiolus (pl; modioli, latin for wheel hub)
vaguely resembles wheel hub (hub of muscles with spokes sticking out)
lateral to corners of mouth
why are modioli important
in relation to functional movements of the oral sphincter
in facial development
what is the function of the frontalis muscle
pulls eyebrows upwards when you raise them in surprise
which 3 muscles alter the position of the oral commisures by moving the modiolus
1) depressor anguli oris
2) levator anguli oris
3) zygomatic major
which muscle/s pulls the commissure downwards when it/they contract/s
depressor anguli oris (because it is fixed at the bottom)
which muscle/s pull the commissure upwards when it/they contract/s
levator anguli oris
zygomatic major (also pulls it slightly BACKWARDS)
which 3 muscles act to elevate or depress upper or lower lips
1) depressor labii inferioris
2) levator labii superioris
3) zygomaticus minor
which muscle/s inserts into and acts to depress the lower lip
depressor labii inferioris
which muscle/s act to elevate the upper lip
levator labii superioris
zygomaticus minor
what is the ‘sulking’ muscle and what does it do / how does it work
the mentalis (mentum; latin for chin)
when these fibres are made shorter the soft tissue is moved up so lower lip moves up and so out (curls it out)
what does the buccinator play important roles in
suckling (survival of babies)
controlling the bolus of food during chewing
which band of fibrous connective tissue defines the posterior boundary of the buccinator
the pterygomandibular raphe
which muscle is posterior to the pterygomandibular raphe + attaches to it
the superior constrictor of the pharynx
how is the pterygomandibular raphe used clinically and why
landmark in IA nerve block procedure because IA nerve goes through mandibular foramen into mandible to supply lower teeth + many of associated gingivi
what is the oxypatalis
connected to the frontalis by tendenous layer (epicranial aponeurosis)
what is the risorius
pulls the modiolus laterally (backwards)
where does the zygomaticus major run
rises from the zygomatic bone that also elevates the corner of the mouth
runs from the mastoid process downwards to blend into the modiolus
where does the depressor angulie oris run
up from below (attached to the mandible)
no superior bony attachment it just ends
has muscular attachment as blends with other muscles at the modiolus
where do the mentalis muscles run
attach superiorly
run downwards and medially
insert into soft tissue of lower lip / chin (mental region)
where does the buccinator run
attached superiorly to the maxilla and INferiorly to the mandible
it is embedded in the cheek
where does the pterygomandibular raphe run
between part of sphenoid bone (one of pterygoid plates) and the mandible
a duct of which salivary gland pierces the buccinator to get into the mouth
parotid gland
branches of which nerve run anteriorly across the face to supply motor function to all the muscles of facial expression
the facial nerve
what type of nerve is the facial nerve
cranial nerve VII (we have 12 cranial nerves emerging from each side of our brain)
so it emerges directly from the brain
how do branches of the facial nerve leave the skull
via foramina and fissures (gaps between bones)
emerge from the skull by travelling through a canal in the petrous part of the temporal bone - come out through a foramen in base of skull that lies just medial just on outside of the mastoid process
what does motor branch of the facial nerve do once its emerged from the skull
almost immediately passes into and through (does NOT supply) the parotid gland which lies on the side of the face just anterior to the ear
in here it breaks up into a series of branches which emerge and run in different directions
what is the correlation between facial nerves running through the parotid gland and IA nerve blocks
if administer it incorrectly
deposit anaethetic solution into the gland + block motor branches of the facial nerve running through it
temporarily paralysing that side of the patient’s face (FACIAL HEMI-PARALYSIS) BUT the teeth are not anaesthetised
describe the branches of the facial nerve supplying the muscles of facial expression
purely motor = all nerves passing along these branches are motor nerve fibres
do nothing else but supply the muscles of facial expression
NO SENSORY FIBRES IN THIS PART OF FACIAL NERVE AT ALL
what 5 groups are the branches of the facial nerve innervating the muscles of facial expression classified into
(hint = depends on region they supply)
1) temporal branches
2) zygomatic branches
3) buccal branches
4) mandibular branches
5) cervical branches
where do the temporal branches run
uowards towards region of the temple (covered by temporalis muscle)
where do the zygomatic branches run
parallel to zygomatic arch
where do the buccal branches run
across cheek
a lot of these as a lot of muscles in the area
where do the mandibular branches run
along inferior border of mandible and just underneath it
where do the cervical branches run
some come down into neck (cervical relates to neck)
what condition results in facial hemi-paralysis and why
bell’s palsy
facial nerve branches going to muscles of facial expressed get screwed up whilst travelleling through the petrous part of temple bone.
while running through this part the nerve gets affected by (in many cases) a virus resulting in this condition
what is the difference between paralysis caused by bells palsy and messing up an IA nerve block
bells palsy lasts for a long time (often weeks) usually spontaneously resolving in most people BUT not all AND even if it does it tends to come back
IA block = resolves after a few hours
what nerve supplies sensory function to the skin covering the face
the trigeminal nerve (cranial nerve V) - theres a right and a left one
(it innervates the oral cavity AND is main sensory nerve for entire face, including all skin covering it and most of cavities within it)
what is present just after the trigeminal nerve leaves the brain
trigeminal ganglion
what is the trigeminal ganglion
where all the cell bodies of the sensory nerve fibres travelling in the nerve are found
which 3 nerves does the trigeminal ganglion give rise to
1) V1 = opthalmic nerve
2) V2 = maxillary nerve
3) V3 = mandibular nerve
(1st, 2nd + 3rd divisions of the trigeminal nerve)
labelled using V because trigeminal nerve is cranial nerve V
why is the trigeminal nerve relevant
branches of it = targets of dental local anaesthetic procedures
when a nerve has been anaesthetised = specific region of the facial skin will become numb (ie lower lip with IA nerve block)
where does its branches run and what part of the facial skin does the V1 opthalmic division of the trigeminal nerve provides sensory innervation to
1) through the orbits
some branches come out of orbit and over forehead passing backwards on the scalp to supply sensation
2) SO forhead and parts of scalp
where does its branches run and what part of the facial skin does the V2 maxillary division of the trigeminal nerve provides sensory innervation to
1) forward underneath orbit and passes under it becoming the infraorbital nerve which then comes out through the infraorbital foramen
2) upper teeth + associated gingivi
infraorbital nerve supplies skin on middle part of anterior aspect of face
where does its branches run and what part of the facial skin does the V3 mandibular division of the trigeminal nerve provides sensory innervation to
1) IA nerve runs inside canal in mandible + divides into 2 nerves at chin one of which being the mental nerve (comes out through mental foramen)
2) skin over lower part of face (lower lip and mucosa on inside of it)
skin infront of and above the ears
what is the significance of the mental nerve given off by the IA nerve
if carry out IA nerve block successfully just as its going in through the mandibular foramen we will anaesthetise some of the associated gingivi and areas supplied by the mental nerve
what does each nerve fibre have on it due to their thinness
a cell body with a nucleus in middle
where are the cell bodies of all sensory nerve fibres running along branches of the trigeminal nerve
trigeminal ganglion (swelling to accomodate all the sensory cell bodies as when theyre collected together they take up a lot of room)
what does ganglion mean when related to a nerve
swelling (where there are cell bodies associated with the nerves)
which other type of nerve supplies some structures in the head and neck and where do these come from
spinal nerves
they emerge from the spinal cord (supply everything else in the body not supplied by the cranial nerves)
