Plastic Surgery -

136
SECTION I Aesthetic Surgery of the Face 6 Anatomy of the aging face Bryan Mendelson and Chin-Ho Wong intraoperative map for the surgeons to safely navigate to the area of interest to correct aging changes. This is most impor- tant in addressing the overriding concern, being the course of the facial nerve branches. An anatomical approach to surgical rejuvenation of the face provides the way to obtaining a “natural” result that is lasting and with minimal morbidity. Regions of the face The traditional approach to assessing the face is to consider the face in thirds (upper, middle, and lower thirds). 2 While useful, this approach limits conceptualization, as it is not based on the function of the face. From a functional perspec- tive, the face has an anterior aspect and a lateral aspect. The anterior face is highly evolved beyond the basic survival needs, specifically, for communication and facial expression. In contrast, the lateral face predominantly covers the struc- tures of mastication. 3 A vertical line descending from the lateral orbital rim is the approximate division between the anterior and lateral zones of the face. Internally, a series of facial retaining ligaments are strategically located along this line to demarcate the anterior from the lateral face (Fig. 6.1). The mimetic muscles of the face are located in the superficial fascia of the anterior face, mostly around the eyes and the mouth. This highly mobile area of the face is designed to allow fine movement and is prone to develop laxity with aging. In contrast, the lateral face is relatively immobile as it overlies the structures to do with mastication, the temporalis, masseter, the parotid gland and its duct, all located deep to the deep fascia. The only superficial muscle in the lateral face is the platysma in the lower third, which extends to the level of the oral commissure. Importantly, the soft tissues of the anterior face are subdi- vided into two parts; that which overlies the skeleton and the larger part that comprises the highly specialized sphincters overlying the bony cavities. 4 Where the soft tissues overlie the orbital and oral cavities they are modified, as there is no deep SYNOPSIS Aging of the face is a multifactorial process that can be explained on an anatomical basis. The face is constructed of five basic layers that are bound together by a system of facial retaining ligaments. To facilitate the mobility needed for facial expression independent of the basic functions of the face, particularly of mastication, a series of soft tissue spaces are incorporated into the architecture of the face. This arrangement, most clearly seen in the scalp, also exists in the rest of the face, although with significant compaction and modifications. This chapter will describe, in detail, the five-layered construct of the face, including the spaces and retaining ligaments, and will highlight the relevance of these structures in the aging face. In addition, the profound impact of aging of the facial skeleton should be appreciated. Understanding these principles will help not only in understanding the aging process but also in designing procedures that are logical and effective in reversing the stigmata of the aging face. Introduction Facial aging is a complex process that is the cumulative effect of simultaneous changes of the many components of the face as well as the interaction of these components with each other. An understanding of the anatomical changes associated with aging is required in order to design effective procedures to rejuvenate various aspects of the aging face. Fundamental to understanding these changes is a firm grounding in the prin- ciples on which the facial soft tissue layers are constructed. 1 This is important because the pathogenesis of facial aging is explained on an anatomical basis, particularly the variations in the onset and outcome of aging seen in different indi- viduals. Understanding the principles on which the facial soft tissues are constructed is the basis for an accurate and reliable © 2013, Elsevier Inc. All rights reserved. 79 Surgical anatomy of the face, SMAS, facial spaces and retaining ligaments fascial layer for support. Accordingly, support does not come from within the cavity beneath, but from the rim of the cavi- ties. The transitions between these areas, while not seen in youth, become increasingly evident with aging. Surgical anatomy of the face, SMAS, facial spaces and retaining ligaments The soft tissue of the face is arranged concentrically into the five basic layers 5,6 : (1) skin; (2) subcutaneous; (3) musculo- aponeurotic layer; (4) areola tissue; and (5) deep fascia. This five-layered arrangement is most clearly seen in the scalp and forehead as a result of evolutionary expansion of the underly- ing cranial vault necessary to accommodate the highly devel- oped frontal lobe in humans. Accordingly, the scalp is an excellent place to study the principles of the layered anatomy (Fig. 6.2). Layer 4 (the loose areolar tissue) is the layer that allows the superficial fascia (defined as the composite flap of layers 1 through 3) to glide over the deep fascia (layer 5). The simplified anatomy over the scalp gives the basic prototype of layer 4. There are not any structures crossing this plane, which is essentially an avascular potential space. At the boundaries of the scalp along the superior temporal line and across the supraorbital rim, the scalp and the forehead are firmly anchored by ligamentous attachments. Vital structures, the nerves and vessels are always located in close proximity to the retaining ligaments. In the face proper, while the prin- ciples of construction remain the same, there is considerably greater complexity. This is due to the compaction resulting from the absence of forward projection of the midface, as occurs in other species, and the predominance of the orbital and oral cavities that limit the availability of a bony platform for attachment of ligaments and muscles. To secure the super- ficial fascia to the facial skeleton, a system of retaining liga- ments bind the dermis to the skeleton, and the components of this system pass through all layers (Figs 6.3, 6.4). 7,8 The structure and composition of each of the 5 layers will now be described in turn. Layer 1: skin The epidermis is a cell-rich layer composed mainly of differ- entiating keratinocytes and a smaller number of pigment pro- ducing melanocytes and antigen-presenting Langerhans cells. The dermis is the outer layer of the structural superficial fascia and comprises predominantly the extracellular matrix secreted Fig. 6.1 Regions of the face. The mobile anterior face is functionally adapted for facial expressions and is separated from the relatively fixed lateral face (shaded), which overlies masticatory structures. A vertical line of retaining ligaments (red) separates the anterior and lateral face. These ligaments are, from above: temporal, lateral orbital, zygomatic, masseteric, and mandibular ligaments. In the anterior face, the mid-cheek is split obliquely into two separate functional parts by the mid-cheek groove (dotted line) related to two cavities: the periorbital part above (blue) and the perioral part below (yellow). (© Dr Levent Efe, CMI.) Fig. 6.2 The face is constructed of five basic layers. This five-layered construct is most evident in the scalp but exists in the rest of the face, with significant modification and compaction for functional adaptation. Layer 4 is the most significantly modified layer, with alternating facial soft tissue spaces and retaining ligaments. Facial nerve branches also transition from deep to superficial in association with the retaining ligaments through layer 4. (© Dr Levent Efe, CMI.)

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Transcript of Plastic Surgery -

  • 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