1 part 1 dermatologic surgery - newbooks services · chapter 1:cutaneous anatomy in dermatologic...

PART 1

Dermatologic Surgery 1

COPYRIG

HTED M

ATERIAL

3

Dermatologic Surgery: Step by Step, First Edition. Edited by Keyvan Nouri.

© 2013 Blackwell Publishing Ltd. Published 2013 by Blackwell Publishing Ltd.

CHAPTER 1

Cutaneous a natomy in d ermatologic s urgery Diana Bolotin 1 , Lucille White 2 , and Murad Alam 3 1 Section of Dermatology, University of Chicago, Chicago, IL, USA 2 Pearland Dermatology, Pearland, TX, USA 3 Department of Dermatology, Northwestern University, Chicago, IL, USA

Introduction

Knowledge of anatomy is essential to every surgeon. The

subtleties of surface anatomy require a special, fi ne - tuned

understanding and are meaningful for a successful der-

matologic procedure in both cutaneous oncology and

cosmetic surgery. Understanding the cutaneous anatomy

of the head and neck is essential in directing appropriate

anesthesia, reducing postoperative complications, and

providing for an acceptable cosmetic outcome. The

anatomy of the face is often regarded in terms of cosmetic

subunits and will be discussed as such in this chapter.

Scalp and f orehead

The frontal hairline separates the forehead from the scalp

superiorly and laterally, and the temporal region is sepa-

rated from the scalp by the temporal hairline. 1 The fore-

head ends at the zygomatic arch inferiorly, while the

inferior scalp is separated from the neck by the nuchal

line inferiorly. The anatomy of the layers of the scalp can

be recalled by the mnemonic S - C - A - L - P, which refers to

the s kin, c onnective tissue, a poneurotic galeal layer, l oose

connective tissue, and p eriosteum. In its most anterior

segment, the skin of the scalp measures about 3 – 4 mm in

thickness and reaches up to 8 mm in the more posterior

segments. Blood vessels, lymphatics, and cutaneous

adnexa reside within the connective tissue layers, while

the underlying musculature connects to the galea apone-

urotica. Muscles of the forehead and scalp include fron-

talis, temporalis, procerus, corrugator supercilii, and

superior fi bers of the orbicularis oculi (Figure 1.1 a).

Deep to the aponeurotic layer is the loose connective

tissue that is largely avascular but does contain perforat-

ing emissary veins. Lastly, the periosteum envelops the

bony skull and contains another layer of vasculature.

Vasculature The blood supply to the forehead and scalp subunits is

provided by branches of both the internal and the exter-

nal carotid arteries. The supratrochlear and supraorbital

arteries supply the central forehead and anterior scalp

and originate from the ophthalmic artery branch of the

internal carotid (Figure 1.1 b). The lateral forehead and

scalp are supplied by the superfi cial temporal and poste-

rior auricular branches of the external carotid artery

(Figure 1.1 c). The posterior scalp is supplied by the

occipital artery, another branch of the external carotid

(Figure 1.1 c).

Nerves The motor and sensory anatomy of the forehead and

scalp are a crucial part of surgery on these subunits.

Motor innervation of the forehead is provided by the

temporal branch of the facial nerve (CN VII). This

branch runs along the temple and the zygomatic arch

but courses more superfi cially superiorly to innervate the

1

4 PART 1: Dermatologic Surgery

(a)

(b)

Deep branch,supraorbital nerve

Facial nerve branchesTemporal

Zygomatic

Supraorbital nerveFrontalis muscleProcerus muscle

Depressor supercilii muscle Corrugator supercilii muscle

Orbicularis oculi muscle

Infratrochlear nerve

Supratrochlear nerve

Deep temporal artery

External nasal artery

Angular artery

Superior labial artery

Inferior labial artery

Dorsal nasal artery

Zygomatico-orbital artery

Supraorbital artery

Frontal branch ofsuperficial temporal artery

Supratrochlear artery

Infraorbital artery

Buccal artery

Facial artery

Mental artery

Submental artery

Transverse facial artery

Figure 1.1 (a) Periorbital and forehead musculature and nerves; (b) facial vasculature; (c) scalp vasculature.

CHAPTER 1: Cutaneous anatomy in dermatologic surgery 5

sidewall, nasal dorsum, tip, alae, soft triangles, and the

columella (Figure 1.3 a). To achieve the best cosmetic

outcome, it is recommended that incision lines during

nasal reconstruction are placed at the borders of these

cosmetic units. The nasal cartilaginous structures, con-

sisting of the lateral nasal and the lower lateral cartilage,

are essential to the integrity of the nose (Figure 1.3 a).

Certain infi ltrative tumors may infi ltrate the lower lateral

nasal cartilage, requiring its excision. Failure to properly

repair the cartilage in this situation may result in the loss

of alar support leading to collapse of the nasal ala and

inhibition of air fl ow into the nose.

Vasculature Similar to the forehead and scalp region, the vasculature

of the nose is derived from both the internal and external

carotid arteries. 3 In fact, arteries supplying the nasal area

make up one of the essential anastomosing sites between

the internal and external carotid arteries. The dorsal nasal

and external nasal branches of the ophthalmic artery,

which branches off from the external carotid, supply the

dorsal nose (Figure 1.3 b). Vascular supply to the nasal

sidewalls, columella, and nasal alae is provided by

branches of the angular artery, a branch of the facial

artery that originates off from the external carotid

(Figure 1.3 b).

Nerves Motor innervations to the procerus muscle at the

nasal root, depressor septi nasi and nasalis muscles are

frontalis muscle at its deep surface. It is therefore most

susceptible to injury at its superfi cial course, which may

result in ipsilateral brow ptosis and pronounced asym-

metry of the face (Figure 1.1 a).

The sensory innervation of the forehead and scalp is

provided by branches of all three divisions of the trigemi-

nal nerve (CN V). The supraorbital and supratrochlear

nerves branch off from the ophthalmic nerve (CNV1) to

supply the scalp up to the vertex (Figure 1.1 a). The zygo-

maticotemporal nerve, arising from the maxillary divi-

sion of the trigeminal nerve (CN V2), supplies sensory

innervations to the anterior temple. The auriculotempo-

ral nerve, a branch of the mandibular division (CN V3),

supplies the rest of the temporal area. Branches of the

cervical spinal nerves (C2, C3) innervate the posterior

scalp.

Lymphatic d rainage The lymphatic drainage of the scalp is collected by the

occipital and posterior auricular lymph nodes (Figure

1.2 ). The basin responsible for lymph drainage of the

forehead subunit is located within the parotid glands

bilaterally.

Mid - f ace

Nasal s ubunit The nasal subunit is generally further subdivided into a

number of cosmetic subunits. 2 These consist of the nasal

Branches of theinternal carotid artery

External carotid artery

Deep temporal artery

Internal maxillary artery

Supraorbital artery

Frontal branch ofsuperficial temporal artery

(c)

Parietal branch ofsuperficial temporal artery

Superficial temporal artery

Occipital artery

Posterior auricular artery


Figure 1.1 (Continued)


Figure 1.2 Lymphatic drainage of the head and neck.

Facial nodesMalar node

Submandibular nodes

Superficial cervical nodeInternal jugular chain

Pre-auricular nodes

Parotid nodes

Post-auricular nodes

Spinal accessory chain

Transverse cervical chain

Occipital nodes

Infraorbital node

Buccinator node

Mandibular nodesSubmental nodes

provided by the zygomatic and buccal branches of the

facial nerve (CN VII) (Figure 1.4 ). The ophthalmic and

maxillary divisions of the trigeminal nerve provide

sensory innervation to the nose. The infratrochlear and

external nasal branches of the ophthalmic division (CN

V1) and the infraorbital branch of the maxillary division

(CN V2) are the primary sources of sensory innervation

for this subunit.

Lymphatic d rainage Lymphatic drainage from the nose is collected primarily

by the submandibular lymph nodes (Figure 1.2 ).

Perioral

The surface anatomy of the lip is divided into the lateral

wings of the cutaneous upper lip, philtrum, lower lip and

the vermillion border which demarcates the red and

white portion of the lips (Figure 1.5 a). 4 The underlying

musculature includes the orbicularis oris, zygomaticus

major and minor, levator anguli oris, depressor anguli

oris, levator labii superioris, depressor labii inferioris,

risorius, mentalis, and the buccinators (Figure 1.5 b). The

nasolabial crease is formed by the cutaneous insertion of

lip elevator musculature.

Vasculature Vascular supply to the lips is provided by the labial arter-

ies that branch off the facial artery. Labial arteries are

frequently resected during biopsies and lip surgery. Intra-

operative ligation or electrosurgery is usually suffi cient to

prevent excessive bleeding.

Nerves Perioral musculature is innervated by the zygomatic,

buccal, marginal mandibular, and cervical branches of

the facial nerve (CN VII) (Figure 1.4 ). The maxillary

division (CN V2) provides sensory innervations to the

upper perioral region via the infraorbital nerve. The

mandibular division (CN V3) contributes to the sensory

innervation of the lower lip via the mental nerve.

Lymphatic d rainage The primary site of lymphatic drainage from the perioral

region is the submental lymph nodes (Figure 1.2 ).

Chin

The cosmetic subunit of the chin is demarcated from the

cheek and lip subunits by the mentolabial crease. Sur-

geons must be aware of the location of the mental


Nerves Motor innervation to the chin is provided by the mar-

ginal mandibular branch of the facial nerve (CN VII).

Injury to this nerve may occur as it crosses the mandible

at the medial edge of the masseter muscle within the

superfi cial soft tissue (Figure 1.4 ). Marginal mandibular

injury is manifested as ipsilateral asymmetry of the lip

and chin during smiling. The mental nerve, entering via

the mental foramen, provides the sensory innervation to

the chin subunit.

foramen that carries the mental nerve and vessels to the

chin, and is located below the second mandibular premo-

lar tooth in the majority of the population. Musculature

of the chin consists of the mentalis, depressor anguli oris,

and depressor labii inferioris (Figure 1.5 b).

Vasculature The mental and submental arteries branch off the

external carotid artery to form the vascular supply of

the chin.

Figure 1.3 (a) Landmarks in nasal anatomy; (b) nasal vasculature and sensory nerves.

Sidewall

Dorsum

Softtriangle

Supratip

(a)

(b)

Infratip

Columella

Lobule

Ala

Alar margin

Tip

External nasalartery and nerve

Lateral nasalartery

Angular artery

Superior labialartery

Transversefacial artery

Infratrochlearnerve

Infratrochlear/dorsal nasal artery

Infraorbitalartery andnerve

Facial artery


branch of the internal carotid system anastomoses with

the angular branch of the facial artery in the vicinity

of the medial canthus (Figure 1.6 b). Supraorbital and

supratrochlear artery branches of the internal carotid

system also supply the upper eyelid area (Figure 1.6 b).

The external carotid artery supplies vasculature to the

lower eyelid by the infraorbital branch of the maxillary

artery and to the lateral periorbital area via the superfi cial

temporal artery.

Nerves Knowledge of neural anatomy of the periocular region is

crucial both to proper anesthesia and to botulinum toxin

treatment of the motor component of the eyelid region.

Sensory innervation is provided by the ophthalmic divi-

sion (CN V1). The glabella is innervated by the supratro-

chlear branch of the ophthalmic division. Sensation to

the lower eyelid is mediated by the infraorbital nerve. The

zygomatic branch of the facial nerve (CN VII) provides

motor innervations to the orbicularis oculi, levator

palpebrae superioris, and parts of the procerus muscles

(Figure 1.4 ). The temporal branch of facial nerve is

responsible for motor innervations of the corrugators

and procerus.

Lymphatic d rainage The submental lymph node basin collects lymphatic

drainage from the chin subunit (Figure 1.2 ).

Periorbital

An understanding of periorbital anatomy is key to avoid-

ance of ectropion and entropion complications of cuta-

neous surgery in this region. The eyelids are made up of

the skin, orbicularis oculi muscle, the tarsus, and the

conjunctiva. 5 Overall structural support to the eyelids is

provided by the medial and lateral canthal tendons. The

superior and inferior lacrimal canaliculi are enveloped by

the medial canthal tendon and are the means of passage

of tears to the lacrimal sac. Disruption of the canaliculi

will lead to a defect in tear drainage. Glands of Zeis and

meibomian glands are large sebaceous glands that reside

in the eyelids (Figure 1.6 a). Glands of Moll are apocrine

glands of the eyelids (Figure 1.6 a).

Vasculature The internal and external carotid arteries provide a vas-

cular supply to the periorbital area. The dorsal nasal

Figure 1.4 Branches of the facial nerve (CN VII).

Branches offacial nerve

Temporal

Zygomatic

Buccal

Cervical

Marginalmandibular Facial

nerve

Parotidgland


subdivided into the medial, zygomatic, buccal, and lateral

cheek units. Each of these has unique surface charac-

teristics and sebaceous nature that must be taken into

account during reconstruction. 6

Vasculature Vasculature supplying the cheek subunit is derived from

the external carotid artery system. The transverse facial

artery supplies the lateral cheek. The angular branch of

the facial artery and the infraorbital artery supply the

medial aspects of the cheeks (Figure 1.1 b). Multiple anas-

tomotic connections within the cheek make this subunit

a highly vascularized skin surface.

Lymphatic d rainage The lymphatic drainage basin of the lateral eyelid area

lies primarily within the parotid lymph nodes. Medial

canthus lymph drains to the submandibular lymph node

basin.

Cheeks

The cheek is the largest facial subunit. Its superior border

is made of the infraorbital rim and zygomatic arch.

The nasolabial and melolabial folds mark the medial

border and the pre - auricular crease makes up the lateral

border of the cheek. The cheek subunit can be further

Figure 1.5 (a) Perioral anatomic landmarks; (b) perioral musculature.

Cutaneoousupper lip

Vermillionborder

Labiomentalgroove

Labialtubercle

Oral fissure

Labialcommissure

Philtrum

(a)

Superficial Deep

Risorius muscle

Platysma muscle

Levator labi superiorisalaeque nasi muscle Levator labi

superioris muscleLevator angularis

oris muscle

Facial nerve,zygomatic branches

Zygomaticusminor muscle

Zygomaticusmajor muscle

Orbicularis oris muscle

Infraorbital nerve

Nasalis muscle

Mental nerve

Mental muscle

Depressor labiinferioris muscle

Depressor angulioris muscle

(b)


of the cheek subunit. The auriculotemporal nerve

innervates parts of the lateral cheek with the buccal

nerve providing sensation to the lateral and buccal

portions. The mental nerve innervates the inferior

medial aspects.

Lymphatic d rainage The parotid and submandibular nodes collect the lym-

phatic drainage from the cheek subunit.

Nerves The muscles of the cheek are supplied with motor inner-

vation by the zygomatic and buccal branches of the

facial nerve (CN VII) (Figure 1.4 ). The infraorbital,

zygomaticofacial, and zygomaticotemporal branches of

the maxillary division of the trigeminal nerve supply

sensation to the medial and zygomatic aspects of the

cheek. Nerves emanating from the mandibular division

of the trigeminal nerve provide sensation to the rest

Figure 1.6 (a) Lacrimal glands and periorbital fat pads; (b) periorbital vascular supply.

Medial fat pad Preaponeuroticfat pad

Temporal fat pad

Medial fat pad

Inferior obliquemuscle

Superior lacrimalpapila and puncta

Pilca semilunarisLacrimal caruncle

Orbital part oflacrimal glandPalpebral part oflacrimal gland

Lacrimal sac

Nasolacrimal duct

Lacrimal canaliculiInferior lacrimal

papilla and puncta

Trochlear

(a)

(b)

Superior/inferiorpalpebral artery

Superior palpebral artery

Lacrimal artery

Angular arteryZygomaticocorbital artery

Superior orbital artery Frontal branch ofsuperficial temporal artery

Transverse facial artery

Facial artery

Dorsal nasal artery


Infraorbital artery


posterior auricular artery. The anterior auricular artery,

which branches off from the superfi cial temporal artery,

supplies the anterior ear.

Nerves Sensory innervation of the ear is complex, with the great

auricular nerve (C2, C3) innervating the lower part of the

lateral and posterior ear. The auriculotemporal branch

(CN V3) innervates the superior lateral ear, and the lesser

occipital nerve provides sensation to the superior poste-

rior ear. The external auditory meatus and conchal bowl

are supplied by fi bers of the glossopharyngeal (CN IX),

auricular branch of the vagus (CN X or Arnold ’ s nerve),

and facial (CN VII) nerves (Figure 1.7 b).

Auricular

The surface anatomy of the ear is complex, with inter-

mixing of multiple convex and concave surfaces. 7 Notable

anatomic landmarks of the ear include the helix, crura,

scaphoid fossa, triangular fossa, conchal bowl, antihelix,

tragus, antitragus, and lobule (Figure 1.7 a). The auricular

cartilage is found in the upper two - thirds of the ear.

Vasculature Blood supply to the auricle is derived entirely from the

external carotid artery system. 8 The lobule and posterior

ear are supplied by the occipital and posterior auricular

arteries. The conchal bowl is supplied by branches of the

Figure 1.7 (a) Auricular anatomic landmarks; (b) Innervation of the ear.

Triangularfossa

Scaphoidfossa

Crura ofantihelix

Antihelix

ConchaCymba

Cavum

Root ofantihelix

Tragus

Intertragicnotch

Lobule

Tubercle(of Darwin)

Helix

Antitragus

(a)

(b)

Cranial nerveIX and X

Great auricularnerve

Auriculotemporalnerve

Lessoroccipitalnerve


identify important underlying structures (Figure 1.8 a).

The superfi cial musculoaponeurotic system (SMAS) is a

fi brous layer of fascia that envelops the platysma and the

superfi cial facial muscles. 9 The easily identifi ed sterno-

cleidomastoid muscle separates the anterior and poste-

rior triangles of the neck. The posterior triangle contains

Erb ’ s point, a landmark of the exit of the spinal accessory

(CN XI), lesser occipital, and great auricular nerves as

well the transverse cervical rami (Figure 1.8 b). Damage

to the spinal accessory nerve may result in the inability

Lymphatic d rainage The posterior aspect of the ear drains to the occipital and

posterior auricular lymph nodes. Anterior ear lymphatic

drainage proceeds to the parotid nodes.

Neck

The superfi cial anatomy of the neck requires anatomic

landmarks indicated by the triangles of the neck to help

Figure 1.8 (a) Anatomic triangles of the neck; (b) Erb ’ s point in posterior triangle of the neck.

Submaxillary triangle

Submental triangle

Superior carotid triangle Posterior triangle

Occipital triangle

Omoclavicular triangle

Sternocleidomastoidmuscle

Inferior carotid triangle

(a)

(b)

External jugular veinErb’s point

Supraclavicular nerve(C3, C4)Trapezius muscle

Platysma muscle

Sternocleidomastoidmuscle

Lesser occipital nerve(C2, C3)Greater auricular nerve(C3, C4)Accessory nerve(CN XI)Transverse cervical nerve(C2, C3)


2. Burget GC , Menick FJ . The subunit principle in nasal recon-

struction . Plast Reconstr Surg 1985 ; 76 : 239 – 47 .

3. Oneal RM , Beil RJ . Surgical anatomy of the nose . Clin Plast

Surg 2010 ; 37 : 191 – 211 .

4. Gassner HG , Rafi i A , Young A , Murakami C , Moe KS ,

Larrabee WF , Jr . Surgical anatomy of the face: implications

for modern face - lift techniques . Arch Facial Plast Surg

2008 ; 10 : 9 – 19 .

5. Most SP , Mobley SR , Larrabee WF , Jr . Anatomy of the eyelids .

Facial Plast Surg Clin North Am 2005 ; 13 : 487 – 92 , v.

6. Dobratz EJ , Hilger PA . Cheek defects . Facial Plast Surg Clin

North Am 2009 ; 17 : 455 – 67 .

7. Shonka DC , Jr ., Park SS . Ear defects . Facial Plast Surg Clin

North Am 2009 ; 17 : 429 – 43 .

8. Park C , Lineaweaver WC , Rumly TO , Buncke HJ . Arterial

supply of the anterior ear . Plast Reconstr Surg 1992 ; 90 :

38 – 44 .

9. Mitz V , Peyronie M . The superfi cial musculo - aponeurotic

system (SMAS) in the parotid and cheek area . Plast Reconstr

Surg 1976 ; 58 : 80 – 8 .

to raise the ipsilateral shoulder. The jugular and carotid

vessels run through the carotid triangle (Figure 1.8 a). The

mental lymph node basin and lingual arteries occupy the

submental triangle. The submaxillary triangle includes

the lingual nerve, artery, and vein, and hypoglossal nerve.

Nerves The cervical branch of the facial nerve (CN VII) provides

the motor innervation to the platysma. Sensory innerva-

tion to this area is provided by the transverse cervical,

supraclavicular, and great auricular nerves.

Lymphatic d rainage Lymphatic nodes of the neck region are the secondary

lymph nodes that receive drainage from most nodes on

the face. These eventually empty into the venous circula-

tion via the thoracic duct.

References

1. Angelos PC , Downs BW . Options for the management of

forehead and scalp defects . Facial Plast Surg Clin North Am

2009 ; 17 : 379 – 93 .

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