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SECT
ION
IA
esth
etic
Sur
ger
y o
f th
e Fa
ce
6
Anat
omy
of th
e ag
ing
face
Bry
an M
end
els
on a
nd
Chin
-Ho W
ong
intr
aope
rati
ve m
ap f
or t
he s
urge
ons
to s
afel
y na
viga
te t
o th
e ar
ea o
f in
tere
st t
o co
rrec
t ag
ing
chan
ges.
Thi
s is
mos
t im
por-
tant
in a
dd
ress
ing
the
over
rid
ing
conc
ern,
bei
ng th
e co
urse
of
the
faci
al n
erve
bra
nche
s. A
n an
atom
ical
app
roac
h to
sur
gica
l re
juve
nati
on o
f th
e fa
ce p
rovi
des
the
way
to
obta
inin
g a
nat
ural
re
sult
tha
t is
last
ing
and
wit
h m
inim
al m
orbi
dit
y.
Regi
ons
of th
e fa
ceT
he t
rad
itio
nal
appr
oach
to
asse
ssin
g th
e fa
ce i
s to
con
sid
er
the
face
in
thir
ds
(upp
er,
mid
dle
, an
d l
ower
thi
rds)
.2 W
hile
us
eful
, th
is a
ppro
ach
limit
s co
ncep
tual
izat
ion,
as
it i
s no
t ba
sed
on
the
func
tion
of
the
face
. Fro
m a
fun
ctio
nal p
ersp
ec-
tive
, the
fac
e ha
s an
ant
erio
r as
pect
and
a l
ater
al a
spec
t. T
he
ante
rior
fac
e is
hig
hly
evol
ved
bey
ond
the
bas
ic s
urvi
val
need
s, s
peci
cal
ly, f
or c
omm
unic
atio
n an
d f
acia
l ex
pres
sion
. In
con
tras
t, th
e la
tera
l fa
ce p
red
omin
antl
y co
vers
the
str
uc-
ture
s of
mas
tica
tion
.3 A
ver
tica
l lin
e d
esce
ndin
g fr
om t
he
late
ral
orbi
tal
rim
is
the
appr
oxim
ate
div
isio
n be
twee
n th
e an
teri
or a
nd l
ater
al z
ones
of
the
face
. In
tern
ally
, a
seri
es o
f fa
cial
ret
aini
ng l
igam
ents
are
str
ateg
ical
ly l
ocat
ed a
long
thi
s lin
e to
dem
arca
te t
he a
nter
ior
from
the
lat
eral
fac
e (F
ig. 6
.1).
The
mim
etic
mus
cles
of
the
face
are
loca
ted
in t
he s
uper
cia
l fa
scia
of
the
ante
rior
fac
e, m
ostl
y ar
ound
the
eye
s an
d t
he
mou
th.
Thi
s hi
ghly
mob
ile a
rea
of t
he f
ace
is d
esig
ned
to
allo
w
ne m
ovem
ent
and
is
pron
e to
dev
elop
lax
ity
wit
h ag
ing.
In
cont
rast
, the
lat
eral
fac
e is
rel
ativ
ely
imm
obile
as
it
over
lies
the
stru
ctur
es to
do
wit
h m
asti
cati
on, t
he te
mpo
ralis
, m
asse
ter,
the
paro
tid
gla
nd a
nd i
ts d
uct,
all
loca
ted
dee
p to
th
e d
eep
fasc
ia. T
he o
nly
supe
rci
al m
uscl
e in
the
late
ral f
ace
is t
he p
laty
sma
in t
he lo
wer
thi
rd, w
hich
ext
end
s to
the
leve
l of
the
ora
l com
mis
sure
.Im
port
antl
y, t
he s
oft
tiss
ues
of t
he a
nter
ior
face
are
sub
di-
vid
ed in
to tw
o pa
rts;
that
whi
ch o
verl
ies
the
skel
eton
and
the
larg
er p
art
that
com
pris
es t
he h
ighl
y sp
ecia
lized
sph
inct
ers
over
lyin
g th
e bo
ny c
avit
ies.
4 Whe
re th
e so
ft ti
ssue
s ov
erlie
the
orbi
tal a
nd o
ral c
avit
ies
they
are
mod
ied
, as
ther
e is
no
dee
p
SY
NO
PS
IS
Agin
g of
the
face
is a
mul
tifac
toria
l pro
cess
that
can
be
expl
aine
d on
an
anat
omic
al b
asis
.
The
face
is c
onst
ruct
ed o
f ve
bas
ic la
yers
that
are
bou
nd to
geth
er
by a
sys
tem
of f
acia
l ret
aini
ng li
gam
ents
.
To fa
cilit
ate
the
mob
ility
need
ed fo
r fac
ial e
xpre
ssio
n in
depe
nden
t of
the
basi
c fu
nctio
ns o
f the
face
, par
ticul
arly
of m
astic
atio
n, a
se
ries
of s
oft t
issu
e sp
aces
are
inco
rpor
ated
into
the
arch
itect
ure
of th
e fa
ce.
This
arr
ange
men
t, m
ost c
lear
ly s
een
in th
e sc
alp,
als
o ex
ists
in
the
rest
of t
he fa
ce, a
lthou
gh w
ith s
igni
can
t com
pact
ion
and
mod
ica
tions
.
This
cha
pter
will
desc
ribe,
in d
etai
l, th
e v
e-la
yere
d co
nstru
ct o
f th
e fa
ce, i
nclu
ding
the
spac
es a
nd re
tain
ing
ligam
ents
, and
will
high
light
the
rele
vanc
e of
thes
e st
ruct
ures
in th
e ag
ing
face
.
In a
dditi
on, t
he p
rofo
und
impa
ct o
f agi
ng o
f the
faci
al s
kele
ton
shou
ld b
e ap
prec
iate
d.
Unde
rsta
ndin
g th
ese
prin
cipl
es w
ill he
lp n
ot o
nly
in u
nder
stan
ding
th
e ag
ing
proc
ess
but a
lso
in d
esig
ning
pro
cedu
res
that
are
logi
cal
and
effe
ctiv
e in
reve
rsin
g th
e st
igm
ata
of th
e ag
ing
face
.
Intr
oduc
tion
Faci
al a
ging
is a
com
plex
pro
cess
that
is th
e cu
mul
ativ
e ef
fect
of
sim
ulta
neou
s ch
ange
s of
the
man
y co
mpo
nent
s of
the
fac
e as
wel
l as
the
inte
ract
ion
of th
ese
com
pone
nts
wit
h ea
ch o
ther
. A
n un
der
stan
din
g of
the
ana
tom
ical
cha
nges
ass
ocia
ted
wit
h ag
ing
is r
equi
red
in
ord
er t
o d
esig
n ef
fect
ive
proc
edur
es t
o re
juve
nate
var
ious
asp
ects
of
the
agin
g fa
ce. F
und
amen
tal t
o un
der
stan
din
g th
ese
chan
ges
is a
rm
gro
und
ing
in th
e pr
in-
cipl
es o
n w
hich
the
fac
ial
soft
tis
sue
laye
rs a
re c
onst
ruct
ed.1
Thi
s is
im
port
ant
beca
use
the
path
ogen
esis
of
faci
al a
ging
is
expl
aine
d o
n an
ana
tom
ical
bas
is, p
arti
cula
rly
the
vari
atio
ns
in t
he o
nset
and
out
com
e of
agi
ng s
een
in d
iffe
rent
ind
i-vi
dua
ls. U
nder
stan
din
g th
e pr
inci
ples
on
whi
ch th
e fa
cial
sof
t ti
ssue
s ar
e co
nstr
ucte
d is
the
basi
s fo
r an
acc
urat
e an
d r
elia
ble
20
13,
Else
vier
Inc.
All
right
s re
serv
ed.
79Su
rgic
al a
nato
my
of th
e fa
ce, S
MAS
, fac
ial s
pace
s an
d re
tain
ing
ligam
ents
fasc
ial l
ayer
for
sup
port
. Acc
ord
ingl
y, s
uppo
rt d
oes
not c
ome
from
wit
hin
the
cavi
ty b
enea
th, b
ut f
rom
the
rim
of
the
cavi
-ti
es.
The
tra
nsit
ions
bet
wee
n th
ese
area
s, w
hile
not
see
n in
yo
uth,
bec
ome
incr
easi
ngly
evi
den
t w
ith
agin
g.
Surg
ical
ana
tom
y of
the
face
, SM
AS,
faci
al s
pace
s an
d re
tain
ing
ligam
ents
The
sof
t ti
ssue
of
the
face
is
arra
nged
con
cent
rica
lly i
nto
the
ve
basi
c la
yers
5,6 :
(1)
skin
; (2
) su
bcut
aneo
us;
(3)
mus
culo
-ap
oneu
roti
c la
yer;
(4)
are
ola
tiss
ue; a
nd (
5) d
eep
fasc
ia. T
his
ve-
laye
red
arr
ange
men
t is
mos
t cle
arly
see
n in
the
scal
p an
d
fore
head
as
a re
sult
of e
volu
tion
ary
expa
nsio
n of
the
und
erly
-in
g cr
ania
l vau
lt n
eces
sary
to a
ccom
mod
ate
the
high
ly d
evel
-op
ed f
ront
al l
obe
in h
uman
s. A
ccor
din
gly,
the
sca
lp i
s an
ex
celle
nt p
lace
to s
tud
y th
e pr
inci
ples
of t
he la
yere
d a
nato
my
(Fig
. 6.
2).
Lay
er 4
(th
e lo
ose
areo
lar
tiss
ue)
is t
he l
ayer
tha
t al
low
s th
e su
per
cial
fas
cia
(de
ned
as
the
com
posi
te
ap o
f la
yers
1 th
roug
h 3)
to g
lide
over
the
dee
p fa
scia
(lay
er 5
). T
he
sim
pli
ed a
nato
my
over
the
sca
lp g
ives
the
bas
ic p
roto
type
of
lay
er 4
. T
here
are
not
any
str
uctu
res
cros
sing
thi
s pl
ane,
w
hich
is
esse
ntia
lly a
n av
ascu
lar
pote
ntia
l sp
ace.
At
the
boun
dar
ies
of t
he s
calp
alo
ng t
he s
uper
ior
tem
pora
l lin
e an
d
acro
ss t
he s
upra
orbi
tal
rim
, th
e sc
alp
and
the
for
ehea
d a
re
rm
ly a
ncho
red
by
ligam
ento
us a
ttac
hmen
ts. V
ital
str
uctu
res,
th
e ne
rves
and
ves
sels
are
alw
ays
loca
ted
in
clos
e pr
oxim
ity
to t
he r
etai
ning
liga
men
ts. I
n th
e fa
ce p
rope
r, w
hile
the
pri
n-ci
ples
of
cons
truc
tion
rem
ain
the
sam
e, t
here
is
cons
ider
ably
gr
eate
r co
mpl
exit
y. T
his
is d
ue t
o th
e co
mpa
ctio
n re
sult
ing
from
the
abs
ence
of
forw
ard
pro
ject
ion
of t
he m
idfa
ce,
as
occu
rs i
n ot
her
spec
ies,
and
the
pre
dom
inan
ce o
f th
e or
bita
l an
d o
ral c
avit
ies
that
lim
it th
e av
aila
bilit
y of
a b
ony
plat
form
fo
r at
tach
men
t of l
igam
ents
and
mus
cles
. To
secu
re th
e su
per-
cia
l fa
scia
to
the
faci
al s
kele
ton,
a s
yste
m o
f re
tain
ing
liga-
men
ts b
ind
the
der
mis
to
the
skel
eton
, an
d t
he c
ompo
nent
s of
thi
s sy
stem
pas
s th
roug
h al
l lay
ers
(Fig
s 6.
3, 6
.4).7
,8
The
str
uctu
re a
nd c
ompo
siti
on o
f ea
ch o
f th
e 5
laye
rs w
ill
now
be
des
crib
ed in
tur
n.
Laye
r 1:
ski
nT
he e
pid
erm
is is
a c
ell-
rich
laye
r co
mpo
sed
mai
nly
of d
iffe
r-en
tiat
ing
kera
tino
cyte
s an
d a
sm
alle
r nu
mbe
r of
pig
men
t pro
-d
ucin
g m
elan
ocyt
es a
nd a
ntig
en-p
rese
ntin
g L
ange
rhan
s ce
lls.
The
der
mis
is th
e ou
ter l
ayer
of t
he s
truc
tura
l sup
erc
ial f
asci
a an
d co
mpr
ises
pre
dom
inan
tly
the
extr
acel
lula
r mat
rix
secr
eted
Fig.
6.1
Reg
ions
of t
he fa
ce. T
he m
obile
ant
erio
r fac
e is
func
tiona
lly a
dapt
ed fo
r fa
cial
exp
ress
ions
and
is s
epar
ated
from
the
rela
tivel
y x
ed la
tera
l fac
e (s
hade
d),
whic
h ov
erlie
s m
astic
ator
y st
ruct
ures
. A v
ertic
al li
ne o
f ret
aini
ng li
gam
ents
(red
) se
para
tes
the
ante
rior a
nd la
tera
l fac
e. T
hese
liga
men
ts a
re, f
rom
abo
ve: t
empo
ral,
late
ral o
rbita
l, zy
gom
atic
, mas
sete
ric, a
nd m
andi
bula
r lig
amen
ts. I
n th
e an
terio
r fa
ce, t
he m
id-c
heek
is s
plit
obliq
uely
into
two
sepa
rate
func
tiona
l par
ts b
y th
e m
id-c
heek
gro
ove
(dot
ted
line)
rela
ted
to tw
o ca
vitie
s: th
e pe
riorb
ital p
art a
bove
(b
lue)
and
the
perio
ral p
art b
elow
(yel
low)
. (
Dr L
even
t Efe
, CM
I.)
Fig.
6.2
The
face
is c
onst
ruct
ed o
f ve
bas
ic la
yers
. Thi
s v
e-la
yere
d co
nstru
ct
is m
ost e
vide
nt in
the
scal
p bu
t exis
ts in
the
rest
of t
he fa
ce, w
ith s
igni
can
t m
odi
catio
n an
d co
mpa
ctio
n fo
r fun
ctio
nal a
dapt
atio
n. L
ayer
4 is
the
mos
t si
gni
cant
ly m
odi
ed la
yer,
with
alte
rnat
ing
faci
al s
oft t
issu
e sp
aces
and
reta
inin
g lig
amen
ts. F
acia
l ner
ve b
ranc
hes
also
tran
sitio
n fro
m d
eep
to s
uper
cia
l in
asso
ciat
ion
with
the
reta
inin
g lig
amen
ts th
roug
h la
yer 4
. (
Dr L
even
t Efe
, CM
I.)
-
80SE
CTIO
N I
Anat
omy
of th
e ag
ing
face
6
The
thi
nner
the
der
mis
, the
mor
e su
scep
tibl
e it
is
to q
ualit
a-ti
ve d
eter
iora
tion
agi
ng c
hang
es.
Laye
r 2:
sub
cuta
neou
s tis
sue
The
sub
cuta
neou
s la
yer
has
two
com
pone
nts:
the
sub
cuta
ne-
ous
fat,
whi
ch p
rovi
des
vol
ume,
and
the
br
ous
reti
nacu
lar
cuti
s th
at b
ind
s th
e d
erm
is to
the
und
erly
ing
SMA
S.9 O
f not
e,
the
reti
nacu
lar
cuti
s is
the
nam
e gi
ven
to t
hat
port
ion
of
the
reta
inin
g lig
amen
t th
at p
asse
s th
roug
h th
e su
bcut
aneo
us
tiss
ues.
The
am
ount
, pr
opor
tion
and
arr
ange
men
t of
eac
h co
mpo
nent
var
y in
dif
fere
nt r
egio
ns o
f th
e fa
ce. I
n th
e sc
alp,
th
e su
bcut
aneo
us la
yer h
as u
nifo
rm th
ickn
ess
and
con
sist
ency
of
xa
tion
to
the
over
lyin
g d
erm
is.
In c
ontr
ast,
in t
he f
ace
prop
er,
the
subc
utan
eous
lay
er h
as s
igni
can
t va
riat
ion
in
thic
knes
s an
d a
ttac
hmen
ts.
In s
peci
aliz
ed a
reas
suc
h as
the
ey
elid
s an
d li
ps, t
his
laye
r is
sign
ica
ntly
com
pact
ed s
uch
that
fa
t may
app
ear n
on-e
xist
ent.
In o
ther
are
as, s
uch
as th
e na
sola
-bi
al s
egm
ent,
it i
s ve
ry t
hick
.4 In
are
as w
ith
thic
k su
bcu-
tane
ous
tiss
ue,
the
reti
nacu
lar
cuti
s le
ngth
ens
sign
ica
ntly
, pr
edis
posi
ng i
ts
bers
to
wea
keni
ng a
nd d
iste
nsio
n w
ith
agin
g. W
ithi
n th
e su
bcut
aneo
us ti
ssue
, the
ove
rall
atta
chm
ent
to th
e ov
erly
ing
der
mis
is s
tron
ger a
nd d
ense
r tha
n th
e at
tach
-m
ent t
o th
e un
der
lyin
g SM
AS.
9 Thi
s is
a r
esul
t of t
he tr
ee-l
ike
arra
ngem
ent
of t
he r
etin
acul
ar c
utis
be
rs (
Fig.
6.3
), w
ith
few
er b
ut t
hick
er
bers
dee
p as
its
ris
es t
hrou
gh t
he S
MA
S th
at p
rogr
essi
vely
div
ide
into
mul
tipl
e n
e m
icro
ligam
ents
as
they
reac
h th
e d
erm
is. T
his
expl
ains
why
it is
eas
ier t
o pe
rfor
m
subc
utan
eous
dis
sect
ion
in t
he d
eepe
r su
bcut
aneo
us l
evel
(ju
st o
n th
e su
rfac
e of
the
und
erly
ing
SMA
S) th
an m
ore
supe
r-c
ially
nea
rer
the
der
mis
, as
ther
e ar
e fe
wer
ret
inac
ular
cut
is
ber
s an
d t
he s
ubcu
tane
ous
fat
here
doe
s no
t at
tach
dir
ectl
y to
the
out
er s
urfa
ce o
f th
e un
der
lyin
g SM
AS.
Furt
herm
ore,
the
ret
inac
ular
cut
is
bers
are
not
uni
form
ac
ross
the
face
, but
var
y in
ori
enta
tion
and
den
sity
acc
ord
ing
to t
he a
nato
my
of t
he u
nder
lyin
g d
eepe
r st
ruct
ures
. As
will
be
app
aren
t w
hen
the
anat
omy
of t
he u
nder
lyin
g L
ayer
4 i
s d
escr
ibed
, at t
he lo
cati
on o
f the
ret
aini
ng li
gam
ents
, the
ver
ti-
cally
ori
enta
ted
ret
inac
ular
cut
is
bers
are
the
mos
t d
ense
an
d a
re t
he m
ost
effe
ctiv
e in
sup
port
ing
for
the
over
lyin
g so
ft
tiss
ues
and
in
so
d
oing
, fo
rms
boun
dar
ies
that
by
brob
last
s. T
ype
I co
llage
n is
the
mos
t ab
und
ant
prot
ein.
O
ther
col
lage
n ty
pes
(III
, V,
VII
), el
asti
n, p
rote
ogly
cans
and
b
rone
ctin
s ar
e pr
esen
t in
sm
alle
r qu
anti
ties
. A r
ich
vasc
ular
pl
exus
is
an i
mpo
rtan
t co
mpo
nent
of
the
der
mis
. T
he t
hick
-ne
ss o
f th
e d
erm
is r
elat
es t
o it
s fu
ncti
on a
nd t
end
s to
be
inve
rsel
y pr
opor
tion
ate
to it
s m
obili
ty. T
he d
erm
is is
thin
nest
in
the
eyel
ids
and
thic
kest
ove
r th
e fo
rehe
ad a
nd th
e na
sal t
ip.
Fig.
6.3
The
reta
inin
g lig
amen
ts o
f the
face
can
be
like
ned
to a
tree
. The
liga
men
ts a
ttach
the
soft
tissu
es to
the
faci
al s
kele
ton
or d
eep
mus
cle
fasc
ia,
pass
ing
thro
ugh
all
ve la
yers
of t
he s
oft t
issu
es. I
t fa
ns o
ut in
a s
erie
s of
bra
nche
s an
d in
serts
into
the
derm
is. A
t diff
eren
t lev
els
of d
isse
ctio
n, it
is g
iven
di
ffere
nt n
ames
, suc
h as
the
retin
acul
ar c
utis
in th
e su
bcut
aneo
us la
yer a
nd li
gam
ents
in th
e su
bSM
AS
leve
l. (
Dr L
even
t Efe
, CM
I.)A
B
Fig.
6.4
Thr
ee m
orph
olog
ical
form
s of
reta
inin
g lig
amen
ts o
f the
face
. (
Dr L
even
t Ef
e, C
MI.)
81Su
rgic
al a
nato
my
of th
e fa
ce, S
MAS
, fac
ial s
pace
s an
d re
tain
ing
ligam
ents
late
ral o
rbit
al th
icke
ning
and
the
mai
n zy
gom
atic
liga
men
t at
its
infe
rola
tera
l bo
rder
and
the
pla
tysm
a at
its
upp
er b
ord
er
by th
e lo
wer
mas
sete
ric
ligam
ent.
The
dee
per
mus
cles
in la
yer
3 pr
ovid
e gr
eate
r fu
ncti
onal
con
trol
of t
he s
phin
cter
s ov
er th
e bo
ny c
avit
ies.
For
the
upp
er t
hird
, the
se a
re t
he c
orru
gato
rs
and
pro
ceru
s, a
nd a
roun
d th
e or
al c
avit
y, th
e el
evat
ors
(zyg
o-m
atic
us m
ajor
and
min
or,
leva
tor
labi
i su
peri
oris
, le
vato
r an
guli
oris
), an
d th
e d
epre
ssor
s (d
epre
ssor
ang
uli o
ris,
dep
ress
or
labi
i inf
erio
ris)
aro
und
the
ora
l sph
inct
er a
nd t
he m
enta
lis.
Laye
r 4
Lay
er 4
is
the
plan
e in
whi
ch d
isse
ctio
n is
per
form
ed i
n su
bSM
AS
face
lifts
. It
is a
n ar
ea o
f si
gni
cant
com
plex
ity
and
co
ntai
ns
the
follo
win
g st
ruct
ures
: (1
) so
ft
tiss
ue
spac
es;
(2) r
etai
ning
liga
men
ts; (
3) d
eep
laye
rs o
f the
intr
insi
c m
uscl
es
pass
ing
from
the
ir b
one
atta
chm
ent
to t
heir
mor
e su
per
cial
so
ft t
issu
e or
igin
; and
(4)
fac
ial n
erve
bra
nche
s, p
assi
ng f
rom
d
eep
to s
uper
cia
l. Fu
ncti
onal
ly, a
ser
ies
of s
oft
tiss
ue s
pace
s ex
ist
in l
ayer
4 t
o al
low
ind
epen
den
t m
ovem
ent
of t
he p
eri-
orbi
tal a
nd p
erio
ral m
uscl
e of
faci
al e
xpre
ssio
ns o
ver
the
dee
p fa
scia
resp
onsi
ble
for m
asti
cati
on d
irec
tly
bene
ath
the
mus
cles
of
fac
ial
expr
essi
on.13
The
ret
aini
ng l
igam
ents
of
the
face
are
st
rate
gica
lly p
lace
d w
ithi
n th
e bo
und
arie
s be
twee
n th
e so
ft
tiss
ue s
pace
s an
d f
unct
ions
to
rein
forc
e th
e bo
und
arie
s (F
ig.
6.6)
. In
the
late
ral f
ace,
imm
edia
tely
in fr
ont o
f the
ear
, ext
end
-in
g 25
30
mm
for
war
d o
f th
e ea
r ca
rtila
ge t
o th
e po
ster
ior
bord
er o
f the
pla
tysm
a, is
a d
iffu
se a
rea
of li
gam
ento
us a
ttac
h-m
ent,
des
crib
ed b
y Fu
rnas
as
the
plat
ysm
a au
ricu
lar
fasc
ia
(PA
F).7
As
no f
acia
l ex
pres
sion
occ
urs
here
, the
der
mis
, sub
-cu
tane
ous
tiss
ue, S
MA
S an
d t
he u
nder
lyin
g pa
roti
d c
apsu
le
(lay
ers
15)
are
bou
nd t
oget
her
as a
n ar
ea o
f re
tain
ing
liga-
men
t. L
ayer
4 i
s re
duc
ed t
o a
laye
r of
fus
ion
here
, wit
hout
a
soft
tis
sue
spac
e. T
he li
gam
ento
us c
hara
cter
of
this
imm
obile
Fig.
6.5
The
den
sity
and
stre
ngth
of t
he re
tinac
ular
cut
is
bers
in th
e su
bcut
aneo
us
laye
r var
ies
in d
iffer
ent a
reas
of t
he fa
ce. W
here
it o
verli
es th
e re
tain
ing
ligam
ents
, th
e b
ers
are
dens
er a
nd o
rient
ed m
ore
verti
cally
. In
thes
e ar
eas,
sha
rp re
leas
e is
us
ually
nec
essa
ry to
rais
e a
subc
utan
eous
ap
. In
cont
rast
, in
area
s ov
erly
ing
a sp
ace,
the
ber
s ar
e le
ss d
ense
and
orie
nted
mor
e ho
rizon
tally
. Her
e, it
is re
lativ
ely
easy
to e
leva
te a
sub
cuta
neou
s fa
celif
t ap
. (
Dr L
even
t Efe
, CM
I.)
Fig.
6.6
Top
ogra
phic
al a
nato
my
of la
yer 4
ove
r the
late
ral f
ace.
Spa
ces
(blu
e),
ligam
ents
(red
) and
the
area
s of
impo
rtant
ana
tom
y (s
tippl
ed).
The
larg
est a
rea
of
liga
men
tous
atta
chm
ent,
the
plat
ysm
a-au
ricul
ar fa
scia
(PAF
), do
min
ates
the
post
erio
r par
t of l
evel
4 a
t the
leas
t mob
ile p
art o
f the
face
. The
late
ral f
ace
trans
ition
s in
to th
e an
terio
r fac
e at
the
verti
cal l
ine
of re
tain
ing
ligam
ents
. Im
med
iate
ly a
bove
and
bel
ow th
e ar
ch o
f the
zyg
oma
are
the
trian
gula
r-sha
ped
area
s th
at c
onta
in th
e im
porta
nt a
nato
my
proc
eedi
ng fr
om th
e la
tera
l int
o th
e an
terio
r fac
e. (
Dr L
even
t Efe
, CM
I.)
com
part
men
taliz
e th
e su
bcut
aneo
us f
at. T
hese
are
as, s
uch
as
the
so-c
alle
d M
cGre
gor
s pa
tch
over
the
bod
y of
the
zygo
ma,
of
ten
requ
ire
shar
p re
leas
e to
mob
ilize
. In
bet
wee
n th
ese
reta
inin
g lig
amen
ts in
laye
r 4
are
loca
ted
the
soft
tiss
ue s
pace
s of
the
fac
e, t
hat
faci
litat
e th
e m
obili
ty o
f th
e su
per
cial
fas
cia
over
the
dee
p fa
scia
. W
here
the
sub
cuta
neou
s fa
t ov
erlie
s a
spac
e, t
he r
etin
acul
ar
bers
are
les
s d
ense
and
ori
enta
ted
m
ore
hori
zont
ally
, as
a r
esul
t of
whi
ch,
the
tiss
ues
tend
to
sepa
rate
wit
h re
lati
ve e
ase,
oft
en w
ith
just
sim
ple
blun
t ng
er
dis
sect
ion
(Fig
. 6.5
). T
his
vari
atio
n in
the
den
sity
and
ori
enta
-ti
on o
f th
e re
tina
cula
r cu
tis
ber
s in
the
sub
cuta
neou
s fa
t is
th
e an
atom
ical
bas
is fo
r th
e co
mpa
rtm
enta
lizat
ion
of th
e su
b-cu
tane
ous
fat
into
dis
cret
e co
mpa
rtm
ents
, des
crib
ed in
det
ail
in C
hapt
er 1
1.1.
10,1
1
Laye
r 3:
mus
culo
-apo
neur
otic
laye
rT
he m
uscl
es o
f fa
cial
exp
ress
ion
are
uniq
ue a
nd f
und
amen
-ta
lly d
iffe
rent
fro
m s
kele
tal
mus
cles
ben
eath
the
dee
p fa
scia
be
caus
e th
ey a
re s
itua
ted
wit
hin
the
supe
rci
al f
asci
a an
d
they
mov
e th
e so
ft ti
ssue
s of
whi
ch th
ey a
re a
par
t. A
ll m
uscl
es
of f
acia
l ex
pres
sion
hav
e ei
ther
all
or t
he m
ajor
ity
of t
heir
co
urse
wit
hin
laye
r 3 a
nd th
ey a
re p
red
omin
antl
y lo
cate
d o
ver
and
aro
und
the
orb
ital
and
ora
l ca
viti
es.
In t
he p
roto
type
sc
alp,
the
occi
pita
l-fr
onta
lis m
oves
the
over
lyin
g so
ft ti
ssue
of
the
fore
head
, w
hile
its
und
ersu
rfac
e gl
ides
ove
r th
e su
bap-
oneu
roti
c sp
ace
(lay
er 4
). L
ayer
3 is
con
tinu
ous
over
the
enti
re
face
, al
thou
gh f
or d
escr
ipti
ve p
urpo
ses,
dif
fere
nt n
ames
are
gi
ven
to c
erta
in p
arts
acc
ord
ing
to t
he s
uper
cia
l m
uscl
e w
ithi
n. I
t is
cal
led
the
gal
ea o
ver
the
scal
p, t
he t
empo
ro-
pari
etal
(su
per
cial
tem
pora
l) f
asci
a ov
er t
he t
empl
e, t
he
orbi
cula
ris
fasc
ia in
the
peri
orbi
tal r
egio
n, th
e su
per
cial
mus
-cu
loap
oneu
roti
c sy
stem
(SM
AS)
ove
r th
e m
id- a
nd lo
wer
face
an
d p
laty
sma
in t
he n
eck.
5,12
Wit
hin
laye
r 3, t
he fa
cial
mus
cles
them
selv
es h
ave
a la
yere
d
con
gura
tion
, wit
h th
e br
oad
, at
mus
cles
form
ing
the
supe
r-c
ial
laye
r th
at c
over
s th
e an
teri
or a
spec
t of
the
fac
e. T
he
fron
talis
cov
ers
the
uppe
r, or
bicu
lari
s oc
uli,
the
mid
dle
and
th
e pl
atys
ma,
and
low
er t
hird
s, r
espe
ctiv
ely.
The
mus
cles
of
this
lay
er h
ave
min
imal
dir
ect
atta
chm
ent
to t
he b
one,
sta
bi-
lized
to th
e sk
elet
on a
t the
ir p
erip
hery
ind
irec
tly
by th
e ve
rti-
cally
ori
enta
ted
ret
aini
ng l
igam
ents
as
note
d e
arlie
r. T
he
fron
talis
is
xed
alo
ng th
e su
peri
or te
mpo
ral l
ine
by th
e su
pe-
rior
tem
pora
l se
ptum
, th
e or
bicu
lari
s oc
uli
late
rally
by
the
-
82SE
CTIO
N I
Anat
omy
of th
e ag
ing
face
6
area
mak
es it
sur
gica
lly u
sefu
l for
sut
ure
xa
tion
. Fur
nas
had
or
igin
ally
des
crib
ed t
he l
ower
par
t of
the
PA
F, t
he p
laty
sma
auri
cula
r lig
amen
t,7 a
lso
nam
ed b
y St
uzin
and
col
leag
ues,
the
paro
tid
cut
aneo
us l
igam
ent5
and
thi
s lig
amen
t w
as s
ubse
-qu
entl
y na
med
the
tym
pano
paro
tid
fas
cia.
14 T
he p
art
of t
he
PAF
imm
edia
tely
in fr
ont o
f the
low
er tr
agus
has
bee
n la
bele
d,
Lor
es
fasc
ia.14
In c
ontr
ast,
in th
e an
teri
or fa
ce w
here
ther
e is
con
sid
erab
le
mov
emen
t ov
er a
nd a
roun
d t
he b
ony
cavi
ties
, the
lig
amen
ts
are
sign
ica
ntly
com
pact
ed a
nd a
rran
ged
aro
und
the
ed
ges
of t
he b
ony
cavi
ties
. The
se b
ound
arie
s pr
ovid
e th
e la
st p
osi-
tion
whe
re t
here
is
und
erly
ing
dee
p fa
scia
for
the
mob
ile
shut
ters
of
the
lids
and
lips
to
be s
uppo
rted
. Im
port
antl
y fo
r th
e su
rgeo
n, t
he r
etai
ning
lig
amen
ts a
lso
act
as t
rans
itio
n po
ints
for
the
fac
ial
nerv
e br
anch
es t
o pa
ss f
rom
dee
p to
su
per
cial
, on
thei
r w
ay t
o in
nerv
ate
thei
r ta
rget
mus
cles
.So
ft t
issu
e sp
aces
of
the
face
are
in
two
form
s: (
1) t
hose
ov
erly
ing
bony
cav
itie
s, s
uch
as t
he p
rese
ptal
spa
ce o
f th
e ey
elid
ove
r th
e or
bit a
nd th
e ve
stib
ule
of th
e or
al c
avit
y, u
nder
th
e lip
s an
d t
he l
ower
nas
olab
ial
segm
ent
of t
he c
heek
and
(2
) th
ose
over
lyin
g th
e bo
ne,
whe
re s
oft
tiss
ue s
pace
s al
low
th
e ov
erly
ing
supe
rci
al f
asci
a to
glid
e fr
eely
ove
r th
e bo
ne.
Laye
r 5
The
dee
p fa
scia
, th
e d
eepe
st s
oft
tiss
ue l
ayer
of
the
face
, is
fo
rmed
by
the
peri
oste
um w
here
it
over
lies
bone
. O
ver
the
late
ral f
ace,
whe
re t
he m
uscl
e of
mas
tica
tion
(te
mpo
ralis
and
m
asse
ter)
ove
rlie
the
bone
, the
dee
p fa
scia
is in
stea
d th
e fa
scia
l co
veri
ng o
f th
e m
uscl
es, t
he d
eep
tem
pora
l fa
scia
abo
ve t
he
zygo
mat
ic a
rch,
and
mas
sete
ric
fasc
ia b
elow
the
arc
h. T
he
paro
tid
fas
cia
is a
lso
part
of
the
dee
p fa
scia
. T
he i
nves
ting
d
eep
cerv
ical
fas
cia
is t
he c
orre
spon
din
g la
yer
in t
he n
eck
whe
re it
cov
ers
the
supr
aom
ohyo
id m
uscl
es a
nd s
plit
s to
form
th
e su
bman
dib
ular
spa
ce t
hat
cont
ains
the
sub
man
dib
ular
gl
and
. The
dee
p fa
scia
, alt
houg
h th
in, i
s to
ugh
and
uny
ield
ing
and
giv
es a
ttac
hmen
t to
the
reta
inin
g lig
amen
ts o
f the
face
. In
the
mob
ile s
hutt
ers
over
the
bon
y ca
viti
es, t
he d
eep
fasc
ia i
s ab
sent
, be
ing
repl
aced
by
a m
obile
lin
ing
der
ived
fro
m t
he
cavi
ties
, tha
t of
the
con
junc
tiva
or
oral
muc
osa.
Anat
omy
over
the
cavi
ties
in
the
skel
eton
The
gen
eral
pat
tern
of
the
ve-
laye
red
ana
tom
y is
mod
ied
w
here
the
sof
t ti
ssue
s ov
erlie
the
orb
ital
, ora
l and
nas
al c
avi-
ties
ove
r th
e an
teri
or fa
ce (F
ig. 6
.7).
Onl
y th
e ou
ter
thre
e la
yers
of
the
com
posi
te c
onti
nue
from
the
peri
pher
y as
the
soft
tiss
ue
over
the
cav
itie
s. T
he S
MA
S la
yer
wit
hin
this
com
posi
te
incl
udes
the
sph
inct
eric
orb
icul
aris
mus
cles
tha
t ex
tend
rig
ht
to t
he f
ree
edge
of
the
soft
tis
sue
aper
ture
of
the
eyel
ids
and
lip
s. T
he r
etai
ning
liga
men
ts, w
hich
are
suc
h a
key
feat
ure
of
the
ve-
laye
red
ana
tom
y, a
re n
ot p
rese
nt o
ver
the
cavi
ties
. T
here
are
thus
ana
tom
ical
var
iati
ons
asso
ciat
e w
ith
thee
func
-ti
onal
tra
nsit
ions
fro
m t
he r
elat
ive
stab
ility
of
the
xe
d
area
s to
the
hig
h m
obili
ty o
f th
e so
ft t
issu
e sh
utte
rs o
ver
the
cavi
ties
. At
the
tran
siti
on, t
o su
ppor
t th
e sh
utte
rs, t
he r
etai
n-in
g lig
amen
ts a
re c
ond
ense
d a
long
the
bon
y or
bita
l rim
(Fi
g.
6.8)
. Thi
s is
the
ana
tom
ical
bas
is f
or t
he p
erio
rbit
al l
igam
ent
arou
nd th
e or
bit,
of w
hich
the
low
er li
d p
art i
s th
e or
bicu
lari
s
Fig.
6.7
The
ana
tom
y ov
er th
e sk
elet
on a
nd o
ver b
ony
cavi
ties
(15
), sh
owin
g th
e re
latio
nshi
p of
the
soft
tissu
e sp
aces
to b
ony
cavi
ty s
pace
s. (
Dr L
even
t Efe
, CM
I.)
Fig.
6.8
The
sys
tem
of r
etai
ning
liga
men
ts s
ituat
ed a
roun
d th
e bo
ny c
aviti
es
stab
ilize
s th
e so
ft tis
sue
over
the
cavi
ties.
( D
r Lev
ent E
fe, C
MI.)
83Fa
cial
spa
ces
the
low
er
tria
ngul
ar
shap
ed
tem
pora
l ar
ea
that
co
ntai
ns
impo
rtan
t an
atom
y, b
y th
e in
feri
or t
empo
ral
sept
um (
ITS)
. T
hese
sep
ti m
erge
at
the
tria
ngul
ar-s
hape
d z
one
of a
dhe
sion
ca
lled
the
tem
pora
l (o
rbit
al)
ligam
ent.1
5 T
he u
pper
tem
pora
l sp
ace
prov
ides
saf
e su
rgic
al a
cces
s to
the
lat
eral
bro
w a
nd
uppe
r m
id-c
heek
. The
spa
ce c
an b
e re
adily
ope
ned
by
blun
t d
isse
ctio
n to
its
bou
ndar
ies.
Onc
e id
enti
ed
, the
bou
ndar
ies
are
then
rel
ease
d b
y pr
ecis
e sh
arp
dis
sect
ion.
The
sup
erio
r te
mpo
ral s
eptu
m c
an b
e re
leas
ed s
harp
ly, t
akin
g ca
re o
nly
to
pres
erve
the
lat
eral
(d
eep)
bra
nch
of t
he s
upra
orbi
tal
nerv
e,
whi
ch r
uns
para
llel t
o th
e se
ptum
abo
ut 0
.5 c
m m
edia
l to
it.19
T
he in
feri
or te
mpo
ral s
eptu
m p
rovi
des
a m
arke
r to
the
impo
r-ta
nt a
nato
my
here
as
the
tem
pora
l bra
nche
s of
the
faci
al n
erve
ar
e lo
cate
d p
aral
lel t
o an
d im
med
iate
ly in
feri
or to
this
sep
tum
. To
rel
ease
the
infe
rior
tem
pora
l sep
tum
, the
roo
f of
the
spa
ce
is g
entl
y lif
ted
off
the
dee
p te
mpo
ral f
asci
a
oor,
whi
ch th
ree-
dim
ensi
onal
izes
the
sep
tum
in
prep
arat
ion
for
its
gent
le
rele
ase
at t
he l
evel
of
the
oo
r, be
arin
g in
min
d t
he f
ront
al
bran
ches
are
loca
ted
und
er th
e ro
of o
f the
low
er te
mpo
ral a
rea
whe
re t
hey
trav
el i
n th
e ce
iling
wit
hin
the
laye
r of
fat
sus
-pe
nded
on
the
und
ersi
de
of t
he t
empo
ropa
riet
al f
asci
a. O
nce
rele
ased
, the
sen
tine
l vei
n co
mes
into
vie
w. T
he s
enti
nel v
ein
is n
ot a
goo
d la
ndm
ark
for
loca
ting
the
tem
pora
l bra
nche
s as
th
ey c
ours
e ce
phal
ad to
the
vein
, tha
t is,
infe
rior
to th
e in
feri
or
tem
pora
l sep
tum
. Thi
s an
atom
y is
als
o re
view
ed in
Cha
pter
7.
reta
inin
g lig
amen
t, w
hich
sta
biliz
es th
e or
bicu
lari
s oc
uli t
o th
e or
bita
l ri
m p
erio
steu
m.
Aro
und
the
ora
l ca
vity
whe
re t
he
boun
dar
y is
less
dis
tinc
t, th
e lig
amen
ts a
rise
mai
nly
from
the
plat
form
of t
he b
ody
of th
e zy
gom
a, a
nd fr
om th
e d
eep
fasc
ia
over
the
mas
sete
r.15
17
The
dee
per
com
pone
nt o
f th
e ey
elid
and
lip
s ar
e d
eriv
ed
from
the
ori
gin
of t
he c
avit
y an
d a
re n
ot a
n ex
tens
ion
of
the
faci
al s
oft
tiss
ues.
In
the
eyel
id,
the
dee
per
lid m
uscl
es
wit
h th
eir
rela
ted
apo
neur
osis
(le
vato
r an
d c
apsu
lopa
lpeb
ral
fasc
iae)
and
fat a
re re
tain
ed b
y th
e fa
scia
l sys
tem
of t
he s
eptu
m
orbi
tale
. The
free
ed
ges
of th
e up
per
and
low
er e
yelid
s ob
tain
th
eir
ligam
ento
us s
uppo
rt f
rom
the
tar
sal
plat
es,
wit
h th
eir
cant
hal
tend
on a
ttac
hmen
ts t
o th
e m
edia
l an
d l
ater
al o
rbit
al
rim
s. I
n th
e pr
etar
sal a
rea,
the
sup
erc
ial a
nd d
eep
lid s
truc
-tu
res,
the
ante
rior
and
pos
teri
or la
mel
lae,
mer
ge. B
ut b
etw
een
the
pret
arsa
l ar
ea o
f th
e lid
and
the
orb
ital
rim
the
lam
ella
e re
mai
n qu
ite
sepa
rate
, i.e
., th
e pr
esep
tal
orbi
cula
ris
doe
s no
t ha
ve a
n at
tach
men
t to
the
sep
tum
orb
ital
e. T
his
is t
he a
na-
tom
ical
bas
is f
or th
e, s
urgi
cally
sig
nic
ant,
pres
epta
l spa
ce o
f th
e lo
wer
lid
. In
the
uppe
r lid
, the
re is
not
an
equi
vale
nt s
pace
as
the
subm
uscu
lar
fat p
ad o
ver
the
supe
rior
orb
ital
rim
con
-ti
nues
on
the
oute
r su
rfac
e of
the
sep
tum
orb
ital
e w
here
it
is a
dhe
rent
to
the
over
lyin
g fa
scia
on
the
und
ersi
de
of t
he
orbi
cula
ris
alm
ost
dow
n to
whe
re t
he l
evat
or c
ross
es i
nto
the
orbi
cula
ris.
The
ext
ent
of t
he v
esti
bule
of
the
oral
cav
ity
cove
ring
the
m
axill
a an
d t
he m
and
ible
has
a m
ajor
im
pact
on
the
susc
ep-
tibi
lity
to a
ging
of
the
over
lyin
g so
ft t
issu
e. T
he s
kele
ton
und
erly
ing
the
spac
e is
not
ava
ilabl
e to
pro
vid
e lig
amen
tous
at
tach
men
t for
sup
port
of t
he s
oft t
issu
es th
at c
over
this
larg
e ar
ea. T
he e
xtre
me
mob
ility
of
the
lip a
nd a
dja
cent
par
t of
the
ch
eek
rend
ers
it s
usce
ptib
le t
o ag
ing
chan
ges
and
the
ind
ica-
tion
for
a l
ower
fac
elif
t is
lar
gely
to
corr
ect
agin
g ch
ange
s in
th
is u
nsup
port
ed t
issu
e.
Faci
al s
pace
sA
lar
ge p
art
of t
he s
ubSM
AS
laye
r 4
cons
ists
of
soft
tis
sue
spa
ces.
T
hese
spa
ces
have
de
ned
bou
ndar
ies
that
are
str
a-te
gica
lly r
einf
orce
d b
y re
tain
ing
ligam
ents
.18 S
igni
can
tly,
th
ese
area
s ar
e by
de
niti
on a
nato
mic
ally
sa
fe s
pace
s t
o d
isse
ct, a
s no
str
uctu
res
cros
ses
wit
hin
and
all
bran
ches
of t
he
faci
al n
erve
are
out
sid
e th
ese
spac
es. A
s th
e ro
of o
f eac
h sp
ace
is t
he l
east
sup
port
ed p
art,
it i
s m
ore
pron
e to
dev
elop
ing
laxi
ty w
ith
agin
g, c
ompa
red
wit
h th
e lig
amen
t-re
info
rced
bo
und
arie
s. T
his
dif
fere
ntia
l la
xity
acc
ount
s fo
r m
uch
of t
he
char
acte
rist
ic c
hang
es th
at o
ccur
wit
h ag
ing
of th
e fa
ce. O
nce
a sp
ace
has
been
sur
gica
lly d
ene
d t
o it
s bo
und
arie
s, t
he
reta
inin
g lig
amen
ts i
n th
e bo
und
ary
can
then
be
prec
isel
y re
leas
ed u
nder
dir
ect
visi
on t
o ac
hiev
e th
e d
esir
ed m
obili
za-
tion
, w
hile
pre
serv
ing
the
vita
l st
ruct
ures
clo
sely
ass
ocia
ted
w
ith
the
ligam
ents
. A b
rief
des
crip
tion
of
surg
ical
ly s
igni
-ca
nt f
acia
l sof
t ti
ssue
spa
ces
is g
iven
bel
ow.
Uppe
r te
mpo
ral s
pace
The
up
per
tem
pora
l sp
ace
sepa
rate
s th
e te
mpo
ropa
riet
al
fasc
ia (
supe
rci
al t
empo
ral
fasc
ia)
from
the
(d
eep)
tem
pora
l fa
scia
and
is s
epar
ated
from
the
fore
head
by
the
supe
rior
tem
-po
ral s
eptu
m (S
TS)
alo
ng th
e su
peri
or te
mpo
ral l
ine
(Fig
. 6.9
). A
nter
oinf
erio
rly,
the
upp
er t
empo
ral s
pace
is s
epar
ated
fro
m
Fig.
6.9
The
upp
er te
mpo
ral s
pace
and
the
reta
inin
g lig
amen
ts o
f the
tem
ple.
The
bo
unda
ries
of th
e sp
ace
are
the
supe
rior t
empo
ral s
eptu
m (S
TS) a
nd th
e in
ferio
r te
mpo
ral s
eptu
m (I
TS),
whic
h ar
e ex
tens
ions
of t
he te
mpo
ral l
igam
ent a
dhes
ion
(TLA
). No
stru
ctur
es c
ross
the
tem
pora
l spa
ce. T
he T
LA c
ontin
ues
med
ially
as
the
supr
aorb
ital l
igam
ento
us a
dhes
ion
(SLA
). In
ferio
r to
the
tem
pora
l spa
ce is
the
trian
gula
r-sha
ped
area
of i
mpo
rtant
ana
tom
y (s
tippl
ed).
Cros
sing
leve
l 4 in
this
ar
ea a
re th
e m
edia
l and
late
ral b
ranc
hes
of th
e zy
gom
atic
tem
pora
l ner
ve (Z
TN) a
nd
the
sent
inel
vei
n. T
he te
mpo
ral b
ranc
hes
of th
e fa
cial
ner
ve (T
FN) c
ours
e on
the
unde
rsid
e of
the
tem
pora
l-par
ieta
l fas
cia
over
the
area
imm
edia
tely
infe
rior t
o th
e in
ferio
r tem
pora
l sep
tum
. The
per
iorb
ital s
eptu
m (P
S, g
reen
) is
on th
e or
bita
l rim
at
the
boun
dary
of t
he o
rbita
l cav
ity. T
he la
tera
l orb
ital t
hick
enin
g (L
OT) a
nd th
e la
tera
l ro
w th
icke
ning
(LBT
) are
par
ts o
f the
per
iorb
ital s
eptu
m. S
ON, s
upra
orbi
tal n
erve
; ZF
N, z
ygom
atic
ofac
ial n
erve
. (
Dr L
even
t Efe
, CM
I.)
-
84SE
CTIO
N I
Anat
omy
of th
e ag
ing
face
6
plan
e al
low
s op
enin
g of
the
jaw
wit
hout
rest
rict
ion
and
avo
ids
exce
ssiv
e d
isto
rtio
n of
the
ove
rlyi
ng s
oft
tiss
ues.
The
roo
f of
th
is s
pace
is f
orm
ed b
y th
e pl
atys
ma.
The
low
er p
rem
asse
ter
spac
e ha
s pr
ofou
nd c
linic
al s
igni
can
ce, a
s it
is th
e an
atom
ical
ba
sis
for
the
dev
elop
men
t of
jow
ls w
ith
agin
g. L
axit
y in
the
ro
of o
f the
spa
ce, p
arti
cula
rly
whe
re it
has
a w
eake
ned
att
ach-
men
t to
the
ante
rior
mas
sete
r by
the
mas
sete
ric
ligam
ents
and
it
s in
feri
or b
ound
ary
whe
re th
ere
is n
o lig
amen
t, m
anif
ests
as
the
labi
oman
dib
ular
fold
and
jow
l, re
spec
tive
ly. T
he re
lati
vely
st
able
xa
tion
at
the
ante
roin
feri
or c
orne
r of
the
pre
mas
sete
r sp
ace
prov
ided
by
the
man
dib
ular
liga
men
t ac
coun
ts f
or t
he
dim
ple
that
is c
omm
only
see
n se
para
ting
the
labi
oman
dib
ular
fo
ld a
bove
and
the
jow
l bel
ow.
Bucc
al s
pace
Thi
s is
one
of
the
dee
p fa
cial
spa
ces,
bei
ng,
like
the
sub-
man
dib
ular
spa
ce (w
hich
con
tain
s th
e su
bman
dib
ular
gla
nd),
dee
p to
the
dee
p fa
scia
(la
yer
5). T
he b
ucca
l sp
ace
is l
ocat
ed
in t
he a
nter
ior
face
, med
ial t
o th
e an
teri
or b
ord
er o
f th
e m
as-
sete
r ab
ove
the
leve
l of
the
oral
com
mis
sure
in y
outh
.20,2
1 The
sp
ace
and
its
cont
ents
, the
buc
cal f
at, f
acili
tate
s m
ovem
ent
of
the
over
lyin
g na
sola
bial
seg
men
t of
the
mid
-che
ek a
s w
ell a
s bu
ffer
ing
this
are
a fr
om e
xces
sive
mot
ion
from
jaw
mov
e-m
ent.
Agi
ng a
nd a
ttri
tion
of
the
boun
dar
ies,
par
ticu
larl
y of
th
e m
asse
teri
c lig
amen
ts i
nfer
iorl
y re
sult
in
the
plat
ysm
a
Fig.
6.1
0 Th
e pr
ezyg
omat
ic s
pace
ove
rlies
the
body
of t
he z
ygom
a. T
he o
rigin
of
the
zygo
mat
ic m
uscl
es e
xtend
s un
der t
he
oor.
The
roof
is fo
rmed
by
the
orbi
cula
ris o
culi
line
by th
e su
borb
icul
aris
ocu
li fa
t (SO
OF).
The
uppe
r lig
amen
tous
bo
rder
form
ed b
y th
e or
bicu
laris
reta
inin
g lig
amen
t is
not a
s st
rong
as
the
zygo
mat
ic li
gam
ent r
einf
orce
d lo
wer b
orde
r. (
Dr L
even
t Efe
, CM
I.)
Fig.
6.1
1 Th
e rh
ombo
idal
-sha
ped
prem
asse
ter s
pace
ove
rlies
the
lowe
r hal
f of t
he
mas
sete
r. Th
e ro
of o
f the
spa
ce is
form
ed b
y th
e pl
atys
ma.
The
pos
terio
r bor
der i
s de
ned
by
the
ante
rior e
dge
of th
e st
rong
PAF
and
the
ante
rior b
orde
r is
rein
forc
ed
by th
e m
asse
teric
liga
men
ts n
ear t
he a
nter
ior e
dge
of th
e m
asse
ter.
The
infe
rior
boun
dary
is m
esen
teric
-like
and
doe
s no
t con
tain
any
liga
men
t. W
eakn
ess
of
atta
chm
ent o
f the
pla
tysm
a ro
of a
t the
infe
rior b
ound
ary
lead
s to
the
form
atio
n
of th
e jo
wl d
irect
ly b
ehin
d th
e st
rong
man
dibu
lar l
igam
ent.
The
bucc
al s
pace
co
ntai
ning
the
bucc
al fa
t is
ante
rior t
o th
e up
per m
asse
teric
liga
men
ts. A
ll fa
cial
ne
rve
bran
ches
cou
rse
arou
nd a
nd o
utsi
de th
e sp
ace.
The
sur
gica
lly im
porta
nt
man
dibu
lar b
ranc
h, a
fter l
eavi
ng th
e x
ed P
AF, c
ours
es u
nder
the
infe
rior b
ound
ary
of th
e sp
ace,
then
rise
s on
to th
e hi
ghly
mob
ile o
uter
sur
face
of t
he m
esen
teric
in
ferio
r bor
der b
efor
e re
achi
ng th
e m
andi
bula
r lig
amen
t. (
Dr L
even
t Efe
, CM
I.)
Prez
ygom
atic
spa
ceT
his
tria
ngul
ar-s
hape
d s
pace
ove
rlie
s th
e bo
dy
of th
e zy
gom
a,
its
oo
r co
veri
ng t
he o
rigi
ns o
f th
e zy
gom
atic
mus
cles
. T
he
spac
e al
low
s th
e in
dep
end
ent d
ispl
acem
ent o
f the
orb
icul
aris
oc
uli
(par
s or
bita
le)
in t
he r
oof
from
the
zyg
omat
ic m
uscl
es
und
er
the
oo
r. C
ontr
acti
on
of
the
over
lyin
g or
bicu
lari
s el
evat
es
the
prez
ygom
atic
so
ft
tiss
ues,
w
hich
re
sult
s in
zy
gom
atic
sm
ile li
nes
(bel
ow th
e cr
ows
feet
) (Fi
g. 6
.10)
. Wit
h th
e la
xity
of
agin
g th
e ro
of o
f th
e sp
ace
rest
s at
a lo
wer
leve
l th
an in
you
th. A
s a
resu
lt, t
here
is a
now
a g
reat
er a
mpl
itud
e of
mov
emen
t on
orb
icul
aris
con
trac
tion
tha
t ha
s th
e ef
fect
of
exag
gera
ting
the
zyg
omat
ic l
ines
wit
h ag
ing.
13,1
6 T
his
agin
g of
the
pre
zygo
mat
ic s
pace
, wit
h bu
lgin
g ov
er i
ts r
oof
acce
n-tu
ated
by
its
wel
l-su
ppor
ted
bou
ndar
ies,
is
the
anat
omic
al
basi
s fo
r th
e cl
inic
al e
ntit
y va
riou
sly
des
crib
ed a
s m
alar
m
ound
s, b
ags
or m
alar
cre
scen
t. T
hese
def
orm
itie
s in
dic
ate
the
pres
ence
of s
igni
can
t lax
ity
and
the
trea
tmen
t is
dir
ecte
d
to t
ight
enin
g th
e la
xity
of
the
roof
and
upp
er l
igam
ento
us
boun
dar
y.
Prem
asse
ter
spac
eT
his
spac
e ov
erlie
s th
e lo
wer
hal
f of t
he m
asse
ter
and
is a
nalo
-go
us t
o th
e te
mpo
ral s
pace
, in
that
it o
verl
ies
the
dee
p fa
scia
of
a m
uscl
e of
mas
tica
tion
(Fig
. 6.1
1).18
Thi
s gl
idin
g so
ft ti
ssue
85Fa
cial
ner
ve b
ranc
hes
surg
ical
tra
nsec
tion
of
the
SMA
S he
re,
so-c
alle
d h
igh
SMA
S tr
anse
ctio
n (i
.e.,
at o
r ab
ove
the
arch
) ha
s be
en g
ener
ally
dis
-co
urag
ed. I
t is
now
app
aren
t tha
t the
ner
ve is
dee
per
than
was
pr
evio
usly
thou
ght a
s it
cro
sses
the
zygo
mat
ic a
rch.
30 A
his
to-
logi
cal s
tud
y co
nrm
ed th
at th
e fr
onta
l bra
nche
s ar
e in
tran
si-
tion
fro
m w
here
the
y ex
it t
he p
arot
id b
elow
the
zyg
omat
ic
arch
, to
whe
re th
ey e
nter
the
und
ersi
de
of th
e te
mpo
ropa
riet
al
fasc
ia s
ome
2 cm
abo
ve th
e ar
ch. T
hey
cour
se in
a ti
ssue
laye
r (l
ayer
4),
just
dee
p to
the
tem
poro
pari
etal
fas
cia
(lay
er 3
) an
d
imm
edia
tely
sup
erc
ial t
o th
e pe
rios
teum
and
abo
ve th
at, t
he
tem
pora
lis f
asci
a (l
ayer
5),
all
alon
g pr
otec
ted
by
a fa
scia
l, fa
tty
laye
r, w
hich
is
an u
pwar
d p
rolo
ngat
ion
of t
he p
arot
id-
mas
sete
ric
fasc
ia a
nd n
amed
the
par
otid
-tem
pora
l fa
scia
.27
Ano
ther
stu
dy
note
d t
he t
empo
ral
bran
ch t
o tr
ansi
tion
to
und
er t
he t
empo
ropa
riet
al f
asci
a (l
ayer
3)
at a
dis
tanc
e of
1.
53
cm a
bove
the
zyg
omat
ic a
rch.
31 T
he t
empo
ral
bran
ch
com
plet
es th
e tr
ansi
tion
to th
e un
der
sid
e of
the
tem
poro
pari
-et
al fa
scia
wel
l bef
ore
the
nerv
e cr
osse
s ce
phal
ad to
the
sent
i-ne
l ve
in.15
Acc
ord
ingl
y, o
nce
the
sent
inel
vei
n is
vis
ualiz
ed
from
th
e te
mpo
ral
aspe
ct,
the
tem
pora
l br
anch
es
wou
ld
alre
ady
be lo
cate
d in
the
roo
f of
the
low
er t
empo
ral a
rea.
The
zyg
omat
ic b
ranc
h ex
its
the
paro
tid
gla
nd d
eep
to t
he
dee
p fa
scia
just
bel
ow th
e zy
gom
a an
d c
epha
lad
to th
e pa
roti
d
duc
t. It
tra
vels
hor
izon
tally
on
the
mas
sete
r w
ith
the
tran
s-ve
rse
faci
al a
rter
y.32
,33
At
the
late
ral
bord
er o
f th
e or
igin
of
zygo
mat
icus
m
ajor
m
uscl
e is
th
e su
bsta
ntiv
e zy
gom
atic
re
tain
ing
ligam
ent
(tha
t at
tach
es t
o th
e bo
dy
of t
he z
ygom
a).
At
the
late
ral
bord
er o
f zy
gom
atic
us m
ajor
, af
ter
a br
anch
is
giv
en o
ff t
o su
pply
the
orb
icul
aris
ocu
li, e
nter
ing
the
mus
cle
at i
ts i
nfer
olat
eral
cor
ner,
the
zygo
mat
ic n
erve
con
-ti
nues
med
ially
and
the
n tr
ansi
tion
s to
the
und
ersi
de
of t
he
mus
cles
it
inne
rvat
es z
ygom
atic
us m
ajor
and
min
or,
and
su
pplie
s th
em f
rom
the
dee
p as
pect
in
clos
e as
soci
atio
n w
ith
the
zygo
mat
ic l
igam
ents
. Car
eful
dis
sect
ion
by v
erti
cal
spre
adin
g of
the
sci
ssor
s is
cru
cial
to
avoi
d d
amag
ing
this
br
anch
her
e.16
,24,
34
The
upp
er b
ucca
l tru
nk e
xits
the
paro
tid
, abo
ut in
line
wit
h,
but
supe
rci
al t
o, t
he p
arot
id d
uct
and
con
tinu
es d
eep
to t
he
inve
stin
g m
asse
ter
fasc
ia. A
ppro
achi
ng t
he a
nter
ior
edge
of
the
mas
sete
r, th
is b
ranc
h le
aves
the
oo
r un
der
the
mas
sete
r fa
scia
in c
lose
ass
ocia
tion
wit
h th
e up
per
key
mas
sete
ric
liga-
men
t.5,3
5 T
he l
ower
buc
cal
trun
k le
aves
the
par
otid
low
er
dow
n, a
t abo
ut th
e le
vel o
f the
ear
lobe
and
rem
ains
und
er th
e m
asse
ter
fasc
ia a
s it
cro
sses
und
er th
e
oor
of th
e pr
emas
sete
r sp
ace
. Sim
ilarl
y, u
pon
appr
oach
ing
the
ante
rior
ed
ge o
f th
e m
asse
ter,
in th
e up
per
mem
bran
ous
boun
dar
y of
the
prem
as-
sete
r sp
ace,
the
low
er b
ucca
l tr
unk
t