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Part I
General
t.me/Dr_Mouayyad_AlbtousH
Evolution ofFacial Bone
Contouring Surgery
SanghoonPark
1
1.1 Beauty Is Bone-Deep
The adage says that “beauty is only skin-deep.” If
this is true, plastic surgery might be only a single
chapter in dermatology. Plastic surgeons often
observe that even successful operations on the
eyes or nose may not substantially alter a patient’s
overall aesthetic appeal. This realization underscores a crucial insight: the shape of the face,
fundamentally sculpted by bone, plays a pivotal
role in dening one’s appearance. The shape of
one’s face is constructed with bone. The distinct
facial features that differentiate Caucasians from
Asians primarily stem from their differing facial
bone structures. Now we can say that “beauty is
bone-deep.”
1.2 Beautiful Facial Structure
Ethnicity plays a signicant role in shaping the
distinct facial bone structures observed across
different populations. For instance, while
Caucasians predominantly exhibit dolichocephalic traits, Asians are more likely to be
brachycephalic (Fig.1.1). This distinction can
be traced back to the developmental patterns of
the skull, inuenced by the fusion of sutures.
The elongated facial features of dolichocephalic individuals resemble those seen in
scaphocephaly, whereas the broader facial
characteristics of brachycephalic individuals
align with the typical appearance of brachycephaly. From a frontal perspective, the racial
differences become even more pronounced:
Caucasian faces tend to be longer and narrower,
giving them an elongated appearance, whereas
Asian faces often appear wider and shorter,
leading to a more square-like impression
(Fig.1.2). This variance in facial structure is so
marked that it allows for the easy distinction
between individuals from Asian and Caucasian
backgrounds during international travels. This
observation brings us to a pivotal question:
“What is the beautiful face?”
S. Park (*)
Center for Facial Bone Surgery, Department of
Plastic Surgery, ID Hospital, Seoul, South Korea
e-mail: spark@idhospital.com
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
S. Park (ed.), Facial Bone Contouring Surgery, https://doi.org/10.1007/978-981-97-4992-8_1
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Fig. 1.1 Comparison of
face in head shape.
Dolichocephalic head
shape in Caucasians
(left) and brachycephalic
head shape in Asians
(right)
S. Park
Table 1.1 Comparison of facial shape between
Caucasians and Asians
Asians Caucasians
Facial shape Brachycephalic Dolichocephalic
Facial index 0.98 1.09
Ideal facial
prole
Ideal facial
proportion
Convex prole Apollonian face
1:1:0.8 1:1:1
Fig. 1.2 Facial index. Facial shape in frontal view is different in terms of length/width ratio. Caucasian face tends
to be long and narrow, while Asian face tends to be wide
and short. Asian face gives a square impression
1.3 Studies onFacial Structure
Studies have been done to describe, compare, and
present the shape of the face. In general, one of
the ways of describing a face is based on the prole of the face. It measures the position, length,
and angle of the upper, middle, and lower face.
This may be based on surface anatomy (anthropometry) or on X-ray (cephalometry). Especially,
cephalometry based on the lateral X-ray led to
more accurate and objective measurements. And
nally, many researchers established the standard
of a beautiful and ideal face type. For instance,
the proportional balance of the upper, middle,
and lower face is ideally 1:1:1, and the position
of the chin should be placed slightly behind the
vertical perpendicular line from nasion. Another
way of describing the facial shape is from the
frontal view. The facial index is a ratio of length
and width of the face in a frontal view. Frontal
cephalometry is also used but less frequently.
Recently, studies are done on three- dimensionally
by using 3D CTs (Table1.1).
1.4 Beauty Keeps Changing
Research on the ideal facial aesthetic reveals signicant differences between Asian and Caucasian
preferences [1]. When it comes to facial vertical
proportions, Asians typically favor a shorter chin
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1 Evolution ofFacial Bone Contouring Surgery
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compared to Caucasians. These aesthetic preferences vary among different nations as well; for
instance, Japanese individuals often prefer a
round and short chin, whereas Chinese individuals tend to favor a sharp and long chin. Such aesthetic standards are not static but have evolved
over decades. This is evident in how the depictions of beauty in ancient paintings may no longer resonate with contemporary tastes. Cultural
trends signicantly inuence beauty standards;
for example, the popularity of a lm star can set
new trends in what is considered beautiful. With
the advent of global communication and transportation, beauty standards are becoming more
globalized and synchronized. Just as SPA brands
can dictate fashion trends, beauty standards are
increasingly shaped by mass media and global
corporations.
1.5 Introduction ofAesthetic
Facial Bone Surgery
A variety of factors necessitate the correction or
reconstruction of facial bones. For example,
injury to facial bone due to motor vehicle accidents requires the correction or reconstruction.
Congenital anomaly and tumor are other common reasons. Surgeries on the facial bone and
craniofacial surgery have been developed by pioneers such as Tessier, Obwegeser, and others
since the 1940s. However, it is quite recent that
aesthetic surgical corrections of the facial bone
was started to be performed. Whitaker and other
craniofacial surgeons started to perform the aesthetic contouring of the face [2]. However, his-
tory of facial bone contouring surgery which is
popular these days started with the introduction
of mandible reduction by Baek [3]. As you can
easily suspect, the aesthetic facial bone surgeries
performed in Asia and Western countries are different in many aspects.
1.6 Why Facial Bone Surgery
Became SoPopular inAsia?
Authors classied the chin shape in frontal view
and investigated the incidence and preference
[4] (Fig.1.3). In Asia, many people have round
chins but want to have a more sharp and
V-shaped chin. This discrepancy explains for
the needs of plastic surgery on the chin. As mentioned before, there is a big difference in facial
morphology between Asians and Westerns. In
the prole and overall facial shape, there are
also big discrepancies in the actual shape and
ideal shape in Asian countries including Korea,
China, Japan, and Southeast Asia. And commonly, patients who undergo facial bone surgery seeks for a softer and feminine impression.
These characteristics are favored especially in
Asian countries. Some transgender patients also
seek for facial feminization through facial bone
surgery. The fact that facial bone surgery can
make a typical Asian face to a small and soft one
is the most appealing reason for its popularity.
Also the prole changes accompanied by facial
bone surgery make people look younger.
Youthful and healthy appearance is universally
admired, especially when people get rich and
surgery became affordable.
Fig. 1.3 Classication of chin. Chin shape may differ, and its preference also may differ among ethnic groups and
nations. Asian people has relatively round or broad chin but want to have triangular or trapezoid chin
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S. Park
1.7 Medical andTechnical
Advances Lower theHuddle
Advancements in medical techniques and anesthesiology have signicantly reduced hospital
stays for patients undergoing facial bone surgery, enabling a quicker return to work after a
brief recovery period. Surgery gets shorter and
speedier and the amount of bleeding becomes
less. Patients, who previously spent a day in
ICU, now have a surgery in outpatient basis.
Most of the techniques used in facial bone surgery have originated from craniofacial surgery.
However, more specic techniques have been
developed recently, and new devices were also
invented. For example, uses of oscillating saw
greatly improved the quality of mandible contouring surgery.
1.8 Evolving Understanding
ofFacial Bone Structure
Improves Strategies
The new understanding underscores the importance of considering not just the angle but the
entire mandible in reduction procedures, a
concept known as total mandible reduction.
Recent investigations have also revealed that a
wide, flat chin, and a U-shaped lower facial
structure often contributes to unsatisfactory
results. The new classification of the zygoma
and the subdivision of the zygomatic body
mark crucial advancements, given the historical lack of detailed description of the zygoma’s subcomponents and their aesthetic
implications. A detailed description of the
subtypes of the zygoma helps determine the
corresponding surgical techniques, offering
insights into the nuanced approaches required
for effective aesthetic enhancement of the
zygomatic area.
1.9 Why Global?
More and more facial bone surgeries are performed globally. The authors have patients coming from all over the world. In some countries,
facial bone surgery is not that popular, and only
few doctors are accustomed to it. Patients told
that they had difculties in communicating with
doctors in their countries. Asians living in
Western countries still have their own tradition
and culture. They still want to have a feminine
and softer look. They complain that doctors in
their countries do not understand exactly what
they want. Surgeons should rst understand the
ethnic characteristics of their faces and later
understand the cultural aesthetic standard and
patient’s motivation for surgery.
1.10 Surgeon’s Mission
By reading this book, authors expect the readers
and surgeons from all over the world would understand this goal and background as well as surgical
skill itself. In aesthetic surgery, patient satisfaction
can only be guaranteed through surgeon’s empathy with the patients’ inner motivation.
References
1. Larrabee WF, Makielski KH. Variations in facial
anatomy with race, sex, and age. In: Larrabee WF,
Makielski KH, Henderson JL, editors. Surgical anatomy of the face. 2nd ed. Philadelphia: Lippincott
Williams & Wilkins; 2004.
2. Whitaker LA, Pertschuk M. Facial skeletal contouring for aesthetic purpose. Plast Reconstr Surg.
1982;69(2):245–53.
3. Baek SM, Kim SS, Bindiger A.The prominent mandibular angle: preoperative management, operative
technique, and results in 42 patients. Plast Reconstr
Surg. 1989;83(2):272–80.
4. Pu L. Aesthetic plastic surgery in Asians: principles
and techniques. Boca Raton: CRC; 2015.
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Anatomic Basis forFacial Bone
Contouring Surgery
SanghoonPark
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2.1 Pearls
1. The variability of the inferior alveolar nerve’s
course among individuals makes it a critical
structure during mandible reduction surgery.
Surgeons must be aware of its entire course
before and throughout the procedure to avoid
complications.
2. The infraorbital nerve, crucial in the midfacial
region for malar reduction or augmentation
surgeries, necessitates precise identication
of the infraorbital foramen’s location preoperatively. Surgeons must exercise caution to
prevent possible trauma to this nerve during
surgical interventions.
3. Facial nerve palsy is a rare but signicant
complication following facial bone contouring surgery, with the temporal and marginal
mandibular branches being particularly susceptible. Surgeons must exercise caution in
areas where these nerve branches are at risk.
4. The risk of damaging major vascular structures, including the facial artery, vein, and retromandibular vein, during mandible reduction
surgery, is highlighted. Such injuries can lead
to profuse bleeding that might be challenging
to control, emphasizing the importance of preventative measures.
S. Park (*)
Center for Facial Bone Surgery, Department of
Plastic Surgery, ID Hospital, Seoul, South Korea
e-mail: spark@idhospital.com
5. Lastly, the crucial role of the mentalis muscle,
the sole elevator of the lower lip and chin, is
discussed. Its proper reattachment is essential
following an anterior vestibular approach to
avoid postoperative chin drooping and a sagging lower lip appearance.
2.2 Introduction
A thorough understanding of facial anatomy is
essential for performing safe and successful
facial bone contouring surgery. The intricate
nature of facial structures means that critical anatomical features such as nerves and vessels must
be handled with utmost care. Irreversible damage
to these elements can have severe consequences
for both the patient and the surgeon. Thus, a deep
knowledge of anatomy is crucial not just for
ensuring safety but also for achieving excellent
surgical results.
Nerve preservation is a key concern in these
surgeries. For instance, in malar reduction surgery, the frontal branch of the facial nerve is particularly at risk of injury in the area just above the
zygomatic arch [1]. In mandible reduction surgeries, such as genioplasty or angle reduction,
the inferior alveolar nerve and the mental nerve
are highly susceptible to injury. Preoperative
assessment of the course of the inferior alveolar
nerve is vital to establish safe and optimal levels
for osteotomy.
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
S. Park (ed.), Facial Bone Contouring Surgery, https://doi.org/10.1007/978-981-97-4992-8_2
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The facial artery, vein, and retromandibular
vein also require careful handling during osteotomy to prevent excessive bleeding and subsequent complications. While experienced surgeons
can often manage such situations, for those at the
beginning of their surgical career, mishandling
these vessels could lead to severe complications.
Therefore, prevention and careful surgical planning are particularly crucial for avoiding major
vessel injury.
The musculature and fat components of the
face, while sometimes considered less critical
than nerves and vessels, also play an important
role in the outcome of surgery. Alterations to
these tissues can lead to postoperative issues like
chin ptosis or hollowed cheeks, affecting patient
satisfaction and comfort.
In the following sections, we will systematically discuss these important anatomical structures, providing a comprehensive guide to their
role and signicance in facial bone contouring
surgery.
S. Park
Fig. 2.1 The course of inferior alveolar nerve and mental
nerve. The inferior alveolar nerve is the largest branch of
the mandibular division of the trigeminal nerve (CN V)
and carries sensory and motor bers. The IAN travels
through the inferior alveolar canal which is positioned at a
variable vertical height. The mental nerve exits the mental
foramen that is located midway between the alveolar and
basal borders of the mandible and is usually below or
slightly anterior to the second premolar tooth
2.3 Nerves
2.3.1 Inferior Alveolar Nerve
(Fig.2.1)
The inferior alveolar nerve (IAN) is a major
branch of the mandibular division of the trigeminal nerve (CN V), responsible for carrying both
sensory and motor bers (Fig.2.1). It branches
off to form the mylohyoid nerve before entering
the mandibular foramen [2]. The position of the
inferior alveolar canal varies and must be carefully assessed in preoperative imaging. Notably,
the canal often curves downward below the level
of the mental foramen. Research by Hwang etal.
indicates an average distance of 4.5 ± 1.9 mm
from the mental foramen to the mandibular canal
[3], suggesting the necessity for osteotomies to
be at least 5–6mm below the foramen to prevent
nerve damage. The IAN, accompanied by the
inferior alveolar vessels, forms the inferior dental
plexus within the canal, giving rise to branches
that provide sensation to the teeth and gums.
Notably, the IAN bifurcates at the mental foramen, with the larger portion emerging as the
mental nerve and a smaller bundle continuing
forward as the incisal bundle.
The mental nerve imparts sensation to the
lower lip’s skin and mucosa, the chin region, and
the anterior teeth’s facial gingiva. It exits the
mental foramen, typically situated below or
slightly anterior to the second premolar tooth,
and divides under the depressor anguli oris muscle into three branches, inuencing the chin’s
skin and the lower lip’s skin and mucosa [4].
2.3.2 Infraorbital Nerve (Fig.2.2)
The infraorbital neurovascular bundle is a critical
structure in midfacial surgeries. The infraorbital
nerve, a signicant cutaneous branch of the maxillary division of the trigeminal nerve (CN V),
exits the infraorbital foramen, positioned
7–10 mm below the infraorbital rim near the
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2 Anatomic Basis forFacial Bone Contouring Surgery
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Fig. 2.2 Infraorbital nerve, zygomaticofacial nerve, and
zygomaticotemporal nerve. ((a) Frontal view (b) Lateral
view) The infraorbital nerve is the largest cutaneous
branch of the maxillary division of the trigeminal nerve
(CN V). After exiting the infraorbital foramen, the infraorbital nerve divides into terminal branches that spread fan-
zygomaticomaxillary suture (Fig.2.2) [3]. Upon
exiting, it branches into multiple divisions that
extend to the lower eyelid, nose, and upper lip,
with some branches permeating the orbicularis
oris muscle to reach the upper lip’s skin. Damage
to this nerve can result in sensory loss or dysesthesia in these areas. Surgeons must therefore
meticulously locate the infraorbital foramen preoperatively to avoid nerve irritation during surgeries like malar reduction or augmentation using
implants. In malar reduction surgery, the place-
like into the lower eyelid, nose, and upper lip. The
zygomaticotemporal and zygomaticofacial nerve pierce
the periorbital sac, traverse the opened subperiosteal space,
and exit the orbit laterally. They innervate sensation to the
skin over their distribution in the area of the lateral orbital
margin and the prominence of the zygomatic body
The zygomaticotemporal nerve ascends toward
the temporal fossa, while the zygomaticofacial
nerve exits laterally over the zygomatic body
prominence. Subperiosteal dissection often
necessitates the division of these nerves, leading
to a loss of sensation in the lateral orbital margin
and zygomatic body. In procedures like malar
reduction surgery, careful dissection near the lateral orbit is essential to identify and, if possible,
preserve these nerves to prevent sensory loss in
the affected areas.
ment of plates and screws should be carefully
planned to avoid nerve disturbance, and in augmentation using implants, the implant must be
2.3.4 Facial Nerve (Fig.2.3)
tailored and positioned to prevent nerve
compression.
The facial nerve (CN VII), a crucial structure in
facial bone contouring surgeries, emerges from
the skull base at the stylomastoid foramen
2.3.3 Zygomaticotemporal/
Zygomaticofacial Nerve
(Fig.2.2)
(Fig.2.3). Positioned medial, deep, and slightly
anterior to the middle of the mastoid process at
the lower end of the tympanomastoid ssure, it
rst branches to the posterior auricular and musDuring subperiosteal dissection near inferolateral
orbital rim, two branches of the sensory zygomatic nerve (a branch of V2)—the zygomaticotemporal and zygomaticofacial nerves—are
identied. These nerves exit the orbit laterally
after traversing the subperiosteal space (Fig.2.2).
cles like the posterior digastric and stylohyoid,
before obliquely entering the parotid gland.
Inside the gland, the nerve divides into temporo-
facial and cervicofacial divisions, situated verti-
cally below the external auditory meatus’s lowest
part. The nerve’s terminal branches, which
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S. Park
Fig. 2.3 Facial nerve, artery, and vein. The main trunk of
the facial nerve (CN VII) emerges from the skull base at
the stylomastoid foramen. The terminal branches of the
facial nerve emerge from the parotid gland and radiate
anteriorly. They are classied as temporal (frontal), zygomatic, buccal, marginal mandibular, and cervical. The
facial artery originates from the external carotid artery,
grooving or passing through the submandibular salivary
include the temporal (frontal), zygomatic, buccal,
marginal mandibular, and cervical branches,
radiate anteriorly from the parotid gland. The
temporal and marginal mandibular branches are
particularly important, as they are at risk of injury
in facial bone contouring surgeries.
The temporal branch travels across the zygomatic arch into the temporal region, necessitating
careful surgical planning during zygomatic arch
dissection in malar reduction surgery to avoid
damage. The exact location of this branch varies,
but it is typically found 8 to 35 mm (average
20 mm) anterior to the external auditory canal
[5].
The marginal mandibular branch, another critical nerve pathway, courses obliquely and anteriorly downward, often originating well behind the
mandible’s posterior border and crossing the
ramus’s lower third. It travels beneath muscles
glands as it rounds the lower border of the mandible. It is
visible on the external surface of the mandible around the
anterior border of the masseter muscle. The facial vein
begins as the angular vein, courses along with the facial
artery above the level of the inferior mandibular border.
The facial vein runs across the surface of the submandibular gland to end in the internal jugular vein
such as the platysma and depressor anguli oris,
innervating the lower lip and chin muscles,
including the depressor labii inferioris, depressor
anguli oris, and mentalis [6]. This branch is particularly susceptible to injury during procedures
like genioplasty, mandible contouring, or hemostasis, often caused by tools like reciprocating
saws, oscillating saws, or electrocautery.
Facial nerve palsy, though rare following
facial bone contouring surgery, can lead to signicant, lasting symptoms like eyebrow drooping
or mouth corner asymmetry. Given the terminal
nature of the temporal branch and its limited
communication with other branches, it is more
prone to damage. Consequently, surgeons must
exercise caution to preserve the integrity of both
the temporal and marginal mandibular branches
during these surgeries.
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2 Anatomic Basis forFacial Bone Contouring Surgery
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2.4 Vessels
2.4.1 Facial Artery (Fig.2.3)
Originating from the external carotid artery, the
facial artery undertakes a cervical course, ascending medially along the mandible and closely paralleling the pharynx (Fig. 2.3). It travels
superiorly beneath the posterior belly of the
digastric and stylohyoid muscles before descending on the medial surface of the mandible, often
grooving or weaving through the submandibular
salivary glands. This artery is visible on the mandible’s external surface near the anterior border
of the masseter muscle and is characteristically
tortuous above the mandible’s inferior border.
2.4.2 Facial Vein (Fig.2.3)
The facial vein, known as the anterior facial vein,
serves as the primary venous drainage for the
face. It originates as the angular vein near the
junction of the nose and eye and typically runs
parallel to the facial artery, positioned posteriorly, above the inferior mandibular border. The
vein crosses the submandibular gland’s surface to
connect with the internal jugular vein.
2.4.3 Retromandibular Vein
Formed by the merging of the supercial temporal and maxillary veins in the upper parotid gland,
the retromandibular vein lies deep to the mandibular neck and lateral to the external carotid
artery. It gives off a descending branch that joins
the facial vein below the mandible’s angle and
then combines with the posterior auricular vein to
form the external jugular vein. These vessels,
particularly during mandible reduction surgeries,
are at risk of damage from deep osteotomies or
cortical shaving, leading to signicant bleeding.
While electrocautery can manage some bleeding,
severe vessel damage may require the use of
hemostatic agents like Surgicel (Ethicon) and
manual compression.
2.5 Muscles
2.5.1 Mentalis Muscle (Fig.2.4)
The mentalis muscles, two conical structures, are
the sole elevators of the lower lip and chin.
Arising from the anterior symphysis’s bony surface, these muscles are separated by a septum and
adipose tissue (Fig.2.4). Their precise reattach-
Fig. 2.4 Mentalis muscle and buccinators muscle. ((a)
Frontal view (b) Lateral view) The mentalis muscles are
paired, conical muscles and function as elevators of the lip
and chin. They arise directly from the bony surface of the
anterior symphysis in a zone between the labial sulcus and
the apices of the lower incisors. The buccinator muscle
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runs a course below the mucogingival junction opposite to
the molars and along the oblique line ascending as the
anterolateral rim of the ascending ramus. The attachments
extend back into the pterygomandibular raphe. The muscle has a unique functional structure allowing for movement comparable to peristaltic motion
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