Dermatologic Surgery

University of Florida, College of Medicine, Gainesville, FL, USA

Private Practice:, Orlando, FL, USA


6.1 Surgical Anatomy

A. Anatomy of Head and Neck Muscles (Figure 6.1)

  • Know function of specific muscles and innervation of head/neck muscles (Table 6-1)

  • Know facial anatomy and important landmarks (Figure 6.2)

  • Location-specific layers:

    • Scalp has five layers: epidermis/dermis, subcutaneous tissue, musculoaponeurotic layer, loose subaponeurotic tissue and periosteum

    • Facial layers (most superficial to deepest): epidermis, dermis, subcutaneous fat, SMAS, muscle, periosteum, bone

  • Superficial musculoaponeurotic system (SMAS)

    • Superficial fibromuscular layer enclosing facial muscles of face/neck; extends from frontalis muscle superiorly to platysma muscle inferiorly, temporalis muscle laterally

    • Allows organized movement of regional muscles during contraction and contributes to appearance of skin tension lines

    • Protective anatomic plane as sensory nerves and axial blood vessels typically located within or between SMAS and subcutaneous fat; motor nerves usually deep to SMAS

    • During facelift, SMAS plicated or pulled to draw skin tight

    • Equivalent of SMAS on scalp is galea aponeurotica, which is a thick inelastic membrane and ideal plane to undermine as it is relatively avascular, separates easily and results in decreased trauma to neurovascular structures

  • Dissection planes (Table 6-2)

    • Undermining should always take place above SMAS with few exceptions

Lip elevators: zygomaticus major/minor, levator labii superioris, levator labii superioris alaeque nasi, levator anguli oris, risorius

Facial expression muscles arise from second branchial archMuscles of mastication arise from first branchial arch


Figure 6.1:
Muscles of the head and neck(Reprint from Nouri, K. Complications in Dermatologic Surgery. Philadelphia, PA: Mosby Elsevier; 2008.)


Figure 6.2:
A: Anatomy/subunits of nose* B: Subunits of the face**C: Anatomy of external ear***Reprint from Nouri, K. Mohs Micrographic Surgery. London, UK: Springer; 2012. **Reprint from Hale E, Karen J, Robins P (eds). Handbook of Dermatologic Surgery. New York, NY:Springer; 2014.

Table 6-1:
Muscles of Head and Neck





Pulls scalp posteriorly

Posterior auricular br. of facial nerve (CN VII)

Frontalis muscle

Elevates eyebrows and wrinkles forehead (horizontal forehead lines)

Temporal br. of CN VII

Orbicularis oculi

Blinking and tight closure of eyelids (‘crow’s feet’), lesser role as brow depressor (depressor supercilii)

Temporal br. of CN VII (upper portion), zygomatic branch of CN VII (lower portion)

Corrugator supercilii

Pulls eyebrows medially and downward (vertical glabellar lines)

Temporal br. of CN VII


Pulls medial portion of eyebrows and glabellar skin downward (horizontal glabellar lines over root of nose)

Zygomatic and buccal br. of CN VII per Bolognia, (rare sources say temporal br.)


Alar flaring and compression (‘bunny lines’ over upper bridge of nose)

Zygomatic and buccal br. of CN VII

Levator labii superioris

Elevates upper lip

Buccal br. of CN VII

Levator labii superioris alaeque nasi

Lifts upper lip, dilates nostrils

Buccal br. of CN VII

Levator anguli oris

Lifts corners of the mouth

Buccal br. of CN VII


Produces smile by drawing back corners of mouth

Marginal mandibular br. of CN VII per Bolognia (other sources say buccal br.)

Zygomaticus major

Main contributor to smile: elevates and draws corner of mouth laterally

Buccal br. of CN VII

Zygomaticus minor

Elevates upper lip

Buccal br. of CN VII


Accounts for cheek dimples in some patients

Orbicularis oris

Closes and purses lips (vertical perioral lip lines)

Buccal or marginal mandibular br. of CN VII


Presses cheek against teeth, allows blowing of cheeks

Buccal br. of CN VII

Depressor anguli oris

Pulls corner of mouth downward (marionette lines → vertical lines at oral commissure)

Marginal mandibular (MM) br. per Bolognia (most other sources say both MM and buccal br.)

Depressor labii inferioris

Depresses lower lip

Marginal mandibular br. CN VII


Protrudes lower lip

Marginal mandibular br. CN VII


Pulls corner of mouth inferiorly, tenses neck (horizontal neck lines)

Marginal mandibular br (upper portion) and cervical br. CN VII

Table 6-2:
Dissection Planes in Head and Neck


Plane of dissection


Superficial to SMAS: superficial to mid fat (more superficial in high-risk areas like zygomatic arch, temporal fossa, etc.)


Deep to SMAS: superficial to periosteum or perichondrium (below nasalis muscle)


Subgaleal plane: superficial to periosteum (below galea aponeurotica), relatively avascular space


Deep fat if small excision; just above deep fascia if larger excision

B. Sensory innervation of Head and Neck (Figure 6.3 and 6.4B, Table 6-3)

  • Trigeminal nerve provides sensory innervation to facial skin along with motor function to muscles of mastication (masseter, medial/lateral pterygoid, temporalis)

    • Three main trigeminal divisions: V1 (ophthalmic), V2 (maxillary) and V3 (mandibular)

    • V1 with five subdivisions: supraorbital (frontal branch), supratrochlear (frontal branch), infratrochlear (nasociliary branch), external nasal (nasociliary branch), and lacrimal nerve

Trigeminal trophic syndrome: injury of CN V (gasserian ganglion), results in dysesthesia often involving nasal ala resulting in sickle-shaped ulceration, treat w/ amitriptyline or carbamazepine

Frey’s syndrome: injury to auriculotemporal branch of CN V in parotid region (carries sympathetic fibers to sweat glands in scalp and parasympathetic fibers to parotid gland), haphazard regeneration leads to redness (vasodilation) and hyperhidrosis of ipsilateral cheek when eating


Figure 6.3:
Sensory innervation of head and neck(Reprint from Nouri, K. Complications in Dermatologic Surgery. Philadelphia, PA: Mosby Elsevier; 2008.)

Table 6-3:
Sensory Innervation of Head and Neck

Nerve Branch

Sensory innervation to:

V1: Ophthalmic branch

Suptratrochlear nerve

Medial forehead, medial upper eyelid, frontal scalp

Supraorbital nerve

Most of forehead, portion of frontoparietal scalp, frontal sinus, upper eyelid

Lacrimal nerve

Lacrimal gland, conjunctivae, lateral eyelids

External nasal branch of anterior ethmoidal (AE) nerve

Nasal dorsum, tip, supratip, and columella

CN V→ ophthalmic → nasociliary → AE nerve → external nasal branch

Reason why zoster lesions on tip of nose can be sign of eye involvement (since both from nasociliary)

Ciliary nerve

Corneal surface

CN V→ ophthalmic → nasociliary → ciliary nerve

Infratrochlear nerve

Root of nose, upper lateral sidewalls, part of medial canthus, lacrimal sac

V2: Maxillary branch

Infraorbital nerve

Medial cheek, upper lip, lower nasal sidewall, nasal ala, lower eyelid

Zygomaticofacial (ZMF) nerve

Malar eminence of cheek


(ZMT) nerve

Temple and supratemporal scalp

Superior alveolar and palatine nerve

Upper teeth, palate, nasal mucosa and gingiva

V3: Mandibular branch (both sensory and motor branches)

Auriculotemporal nerve

Anterior upper half of ear, tragus, preauricular cheek, anterior ½ of meatus, TMJ, external tympanic membrane, temple, temporoparietal scalp

Buccal nerve

Cheek, buccal mucosa and gingiva

Inferior alveolar

Mandibular teeth

Mental nerve

Chin, lower lip

Lingual nerve

Anterior 2/3 of tongue (somatic sensation), floor of mouth, lower gingiva

Cervical plexus (C2-C4)

Lesser occipital nerve C2

Neck and postauricular scalp, posterior upper half of ear

Greater occipital nerve C2

Occipital scalp

Transverse cervical nerve C2 and C3

Anterior neck

Supraclavicular nerve C3 and C4

Anterior chest, clavicle and shoulder

Greater auricular nerve C2 and C3

Lateral neck, angle of jaw, inferior lateral cheek, anterior/posterior lower half of ear (include ear lobule), mastoid process, and postauricular skin

Other sensory nerves

Facial nerve

CN VII → chorda tympani

CN VII → small branches (minor role in sensory)

Taste sensation (anterior 2/3 tongue via chorda tympani), small portion of auditory meatus, concha bowl (variably innervated by branches of vagus and facial nerves), soft palate, pharynx

Auricular branch of vagus nerve (CN X)

CN X → auricular branch

Posterior ½ of tympanic membrane and posterior wall of external auditory meatus

Glossopharyngeal (CN IX)
Taste and somatic sensation to posterior 1/3 of tongue

Know innervation to following areas:

  • Great toe web space: deep peroneal nerve

  • Heel, sole, volar toes: posterior tibial nerve branches (calcaneal and medial/lateral plantar nerves)

  • Dorsum of foot: superficial peroneal nerve

  • Lateral malleolus, 5th toe: sural nerve

  • Lateral sole: sural nerve

  • Medial malleolus: saphenous nerve


Figure 6.4:
A. Sensory innervation of the lower extremity B. Sensory innervation of the ear(Reprint from Nouri, K. Complications in Dermatologic Surgery. Philadelphia, PA: Mosby Elsevier; 2008.)

C. Motor Innervation of Head and Neck

Mnemonic for CN VII branches: To Zanzibar By Motor Car

  • Facial nerve exits skull via stylomastoid foramen, enters parotid gland, and then divides into five branches: temporal, zygomatic, buccal, marginal mandibular and cervical

  • Facial nerve innervates muscles of facial expression (motor) and small component sensory innervation (external auditory meatus, anterior tongue)

  • All motor nerves innervate respective muscles on muscle’s underside with few exceptions

  • Three danger zones areas in head/neck for motor nerve injury (Table 6-4)

Table 6-4:
Danger Zones for Motor Nerve Injury (Figure 6.5)





Spinal accessory nerve


Nerve courses within posterior triangle of neck in superficial plane, emerges posterior to SCM within 2cm of Erb’s point

Erb’s point: midpoint of posterior border of SCM (point where cervical plexus emerges)

Innervates trapezius muscle

Shoulder drooping, winged scapula, inability to abduct arm

Temporal branch of facial nerve (CN VII)

Danger zone between following two lines: ear lobe to lateral edge of eyebrow and tragus to lateral highest forehead crease – nerve most superficial over bony prominence

Nerve courses from a point located 0.5cm inferior to the tragus to a point 2cm superior and lateral to tail of eyebrow before diving beneath frontalis muscle

Innervates frontalis muscle

Inability to raise eyebrow, drooping of ipsilateral eyebrow, inability to close eye completely

Marginal mandibular branch of facial nerve


Most susceptible to injury anterior to angle of mandible during undermining due to superficial location over bony prominence

Innervates lip depressors

Asymmetry with resultant crooked smile and drooling on affected side

D. Arterial Supply of Head and Neck (Figure 6.6, Table 6-5)

  • Vascular supply from external and internal carotid artery

Table 6-5:
Arterial Supply to Head/Neck

External Carotid Artery (ECA) Branches

Internal Carotid Artery (ICA) Branches

1. Facial artery (terminates by medial canthus)

1. Ophthalmic artery

 (a) Angular artery

 (a) Lacrimal

 (b) Superior labial artery

 (b) Supratrochlear (frontal) artery

Axial blood supply for midline forehead flap; success of flap depends on preservation of this artery

 (c) Inferior labial artery

 (c) Supraorbital artery

 (d) Lateral nasal artery

 (d) Posterior ethmoidal

2. Superficial temporal artery

 (e) Anterior ethmoidal

 (a) Transverse facial artery

 (f) Dorsal nasal artery

 (b) Middle temporal artery

 (g) Anterior ciliary artery

 (c) Anterior auricular artery

 (h) Central retinal artery

 (d) Frontal branch

 (e) Parietal branch

3. Maxillary artery

 (a) Infraorbital artery

 (b) Buccal artery

 (c) Inferior alveolar artery

4. Occipital artery

5. Posterior auricular artery

6. Lingual artery


Figure 6.5:
Danger zones of the face(Reprint from Nouri K. Mohs Micrographic Surgery. London, UK: Springer; 2012.)

Of note, facial artery runs superficially across lower border of mandible and then travels toward nose as angular artery


Figure 6.6:
Vascular supply to face(Reprint from Nouri K. Complications in Dermatologic Surgery. Philadelphia, PA: Mosby Elsevier; 2008.)

E. Lymph Nodes of the Head and Neck

Lymph node location

Locations drained by respective lymph nodes

Postauricular nodes

Upper posterior ear, mastoid, posterior parietal and temporal scalp

Occipital nodes

Posterior aspect of scalp

Parotid nodes(includes preauricular and infrauricular nodes)

Upper and lateral face: frontolateral scalp, anterior surface of ears, lower cheeks, forehead, lateral canthal area

Submental nodes

Central and lower face: central lower lip, chin, floor of mouth, anterior tongue, and chin

Submandibular nodes

Central and lower face: gingival and mucous membranes, lower eyelids, anterior two thirds of tongue, lips, nose, medial cheeks

Lymphatic drainage of face in downward diagonal direction.

6.2 Excisions, Flaps, and Grafts

A. Excisions

Basic Excision Principles

  • Fusiform excision with length typically three times longer than width; sides of wound should be vertical with a flat, even wound base at the level of subcutaneous fat or fascia

  • Excision should always be made parallel to skin tension lines for best cosmetic result

  • Skin tension lines: fine wrinkles seen in aged face typically perpendicular to underlying long axis of muscle; lines from tension exerted on skin by facial expression muscles, collagen, and elastic fibers

  • Variants of elliptical excision can be used in particular locations for a better cosmetic result:

    • S-plasty or lazy S repair: performed if excision over convex surfaces (ie. jaw, shin, forearm) to ↓ contraction and buckling along length of scar for better cosmetic result

    • M-plasty: effective for reducing length of scar when it would encroach on important structures (ie. corner of mouth, eyebrow)

    • Crescent excision: results in shorter curvilinear scar and can be oriented along curved skin tension lines or cosmetic subunit junction lines (ie. cheek, chin)

  • Of note, lesions on the lip with a size equal or less to 1/3 the length of lower lip can be repaired with primary closure after wedge excision due to laxity of the lip

Cosmetic subunits

  • Major structural areas of face separated by contour lines or boundaries

  • Units arranged by similarity in topographic anatomy, texture, pigmentation, amount of sun exposure, sebaceous gland and hair type/density

  • Major units: forehead, temples, eyelids, nose, cheeks, upper and lower lips, chin and ears

  • Units within nose: dorsum, nasal sidewall, soft triangle, tip, alar lobule, columella

  • Contour lines between cosmetic units is an ideal place to hide surgical scars (i.e., hairline, alar or nasolabial crease, eyebrows, philtrum, vermilion cutaneous interface)

  • Defects should be repaired with tissue from within the same cosmetic unit to preserve consistency and for best cosmetic outcome

Wounds may contract as fast as 0.75 mm/day

Wound Healing

  • Primary vs. secondary intention healing

    • Primary intention: direct closure of wound by approximating wound edges together (side to side closure, flaps, grafts)

    • Secondary intention: wound left open and allowed to heal from inner to outer surface

  • Wound contraction (maximal at 2 months after re-epithelialization)

    • Concave skin wounds (ie. inner ear, nasal alar crease, temple, conchal bowl) heal with best with secondary intention (vs. primary)

    • Convex surfaces (ie. malar cheek, vermilion border of lip, tip of nose) not optimal for healing by secondary intention and may cause ectropion or eclabion in areas with free margin of skin (nose, eyelids)

  • Wound healing: Four sequential overlapping stages

    • Vascular phase: thrombin/exposed collagen results in stimulation of platelets, which release PDGF and other factors important for angiogenesis and fibroplasia → platelets aggregate forming hemostatic plug and damaged vessels are pressed together causing adherence to one another → overall result is hemostasis

    • Inflammatory phase: neutrophils (first cell to arrive, often within first hour after injury) and macrophages (most important cell in healing process) recruited to wound site, phagocytosis of debris/bacteria

    • Proliferative phase: re-epithelialization within first 24 h of injury, production of collagen (type III); macrophages release fibronectin (which attracts fibroblasts) and other factors which induce angiogenesis and granulation tissue formation

    • Wound contraction and remodeling: contraction via myofibroblasts, maximum strength of scar reached is 70-80% of original strength prior to injury

Table 6-6:
Types of Superficial Repair




Use for:

Simple interrupted

+ provides wound eversion

+ allows high-low correction

+ individual sutures removed without disturbing remaining

− ↑ overall closure time

− ↑ net suture bulk with more prominent suture marks, skin irritation


+ ↓ closure time

+ suture bulk spread over entire wound

− integrity depends solely on knots on either end

Use with minimal tension wounds

Vertical mattress

+ relieves tension

+ wound eversion

− tendency to leave permanent suture marks

High tension areas

Horizontal mattress

+ ↑ holding tension

+ wound eversion

+ hemostasis

− ↑ tissue ischemia

− railroad track marks

Tight situation where vertical mattress not possible

Running subcuticular

+ avoids any suture marks along skin surface

− ↑ reactivity

− ↑ overall closure time

Minimal tension and mobility

Scar strength: 5% at 2 weeks 15% at 3 weeks 40% at 6 weeks 80% at 1 year

Best with polypropylene glycol due to ↓ tissue reactivity

B. Flaps

  • May be classified based on:

    • Blood Supply

      • Axial pattern flap-relies on specific artery for blood supply

      • Random pattern flap

    • Primary Motion

      • Advancement

      • Rotation

      • Transposition

  • Flaps can redirect wound tension vector and recruit tissue laxity from adjacent skin

  • Be able to identify type of flap based on outline of scar (Table 6-7)

C. Grafts

  • Skin completely detached from donor site; full-thickness, split-thickness and composite

Full-Thickness Skin Graft (FTSG)

  • Epidermis + full thickness dermis

  • Advantages: better overall cosmesis (compared to STSG), less wound contracture, retention of appendages

  • Disadvantages: increased metabolic demand (due to increased thickness) thus size of FTSG limited, increased rate of graft failure since more vulnerable to necrosis

  • Donor sites: preauricular, postauricular, conchal bowl, nasolabial, supraclavicular, inner arm

  • Typically FTSGs placed over convex and concave sites (ie. medial canthus, helix, nasal tip, and nasal ala); must remove fat as this may compromise viability of graft

  • Graft should be 10-20% larger than defect size to prevent undersized graft and account for graft contracture (typically up to 15% contraction)

  • One week postop: violaceous appearance (resist debridement even if black and potentially necrotic) → monitor site for another week as even if necrotic, can serve as biologic dressing

  • Two weeks postop: often changes from a violaceous to pink color

Table 6-7:
Types of Flaps: Advancement, Rotation and Transpositional

Type of Flap



Advancement Flap

Unidirectional, uncomplicated advancement of leading edge of flap

Unilateral advancement flap (U-plasty)

Defect excised as square and incision extended in same direction on two but opposite parallel sides of defect; burow’s triangle created at end of each extension and flap slides over defect creating U-shaped scar


Bilateral advancement flap (H-plasty)

Double U-plasty or double advancement flap; two U-plasty flaps created as mirror images of one another; most useful for scalp and eyebrow defects (H-plasty)


Bilateral T-plasty (A-T, O-T)

Linear repair of wound perpendicular to pre-existing cosmetic boundary; useful for above brow, upper cutaneous lateral lip


Burow’s advancement flap

Defect excised in shape of equilateral triangle and one arm of triangle extended; burow’s triangle created at contralateral side of extension and tissue slides to cover defect


Island pedicle flap

Special advancement flap: most of vascular supply from a subcutaneous pedicle (remains attached to central portion of flap) and all dermal margins of flap severed before advanced


Rotation flap

Recruits adjacent tissue laxity and directs wound tension vectors away from primary surgical defect; curvilinear incision (arc) adjacent to primary defect and flap rotated to primary defect site; useful for scalp, temple, and medial cheek defects

Dorsal nasal rotation flap

Special type of rotation flap; long sweeping arc that involves rotation of entire nasal dorsum (elevated at level of perichondrium or periosteum)


Bilateral advancement rotational flap (O – Z flap)

Bilateral rotation flap converting circular defect into a Z-shaped incision line, most useful on scalp

(can be purely rotational or advancement with rotation)


Transposition Flap

Most complex design, redirects wound closure tension, moves tissue from area of surplus to area of need by transpositioning across intervening islands of unaffected tissue

Rhomboid transposition flap

Rhomboidal-shaped flap created adjacent to round or oval defect and transposed into defect


Bilobed transposition flap

Recruits tissue from proximal nasal dorsum (more laxity) and transfers to defect, useful on distal nose


Nasolabial transposition flap

Flap from medial cheek adjacent to melolabial fold transposed to alar wound, useful in lateral and central alar wounds



Useful for scars crossing relaxed tension lines or releasing contractures (redistributes tension over wound)


Paramedian forehead flap

2 stage flap for repair of subtotal to total nasal defects; forehead flap designed vertically to preserve supratrochlear artery supply; flap rotated 180 degrees and sewn into nasal defect; 2-3 weeks later pedicle divided and repositioned

Axial pattern flap as well


Figure 6.7:
A: Advancement flap* B: Advancement flap*C: Bilobed flap* D: Bilobed flap*E: Island pedicle flap* F: Island pedicle flap**Reprint from Nouri, K. Mohs Micrographic Surgery. London, UK: Springer; 2012.

Thin STSG: 0.005 to 0.012 in

Medium STSG: 0.012 to 0.018 in

Thick STSG: 0.018 to 0.030 in

Split-Thickness Skin Graft (STSG)

  • Epidermis + partial thickness dermis

  • Advantages: ability to cover large defects (especially if graft fenestrated), higher likelihood of survival as less metabolic demand, allows for detection of tumor recurrence in cutaneous oncology

  • Disadvantages: less cosmetically desirable color and texture, granulation tissue at donor site, increased contracture at wound site (more than with FTSG), lack adnexal structures (do not produce sebum, hair, sweat)

  • Donor sites: buttocks, thighs, arms, abdomen

  • 1 week postop: pink to skin-colored

Composite Graft

  • Epidermis + dermis + one more component (typically cartilage)

  • Advantages: ability to restore missing cartilage in primary defect, maintains proper tissue architecture and function

  • Disadvantages: highest metabolic demand (thus, highest likelihood of failure), size limited (due to blood supply)

  • Donor sites: helix of ear, conchal bowl

  • Most commonly used in nose (commonly nasal ala → cartilage restores proper function and prevents alar collapse during inspiration) and donor site typically crus of helix of ear

Stages of Graft Survival (Table 6-8)

  • Skin graft must re-establish blood supply at recipient sites

  • Three stages: imbibition, inosculation, neovascularization

Table 6-8:
Stages of Skin Graft Survival



1. Imbibition

First 24-48 hours (ischemic period)

Graft sustained by plasma exudate from wound bed

Fibrin attaches graft to new bed

Graft becomes edematous, ↑ weight by up to 40%

2. Inosculation

Begins 48-72 hours, lasts up to 7-10 days (graft vessels anastomose)

Revascularization linking dermal vessels in graft to recipient bed

Rationale for delayed grafting over sites devoid of perichondrium or periosteum (allows formation of granulation tissue with ↑ survival rate)

3. Neovascularization

Occurs temporally with inosculation

Capillary ingrowth from recipient wound base and sidewalls to graft

If optimal conditions, full circulation reestablished within 4-7 days

4. Maturation

Occurs months later

Reinnervation of graft typically within 2 months of graft but may not be complete for months to years (full sensation may never fully return)

6.3 Surgical Complications


  • Risk of bleeding greatest in first 48 hours (especially in immediate posotoperative period)

  • Provides medium for bacteria, prevents wound healing, ↑ wound tension (± dehiscence)

  • Two types of hematoma: stable and expanding

  • Stable hematoma

    • Non-expanding ecchymotic firm to fluctuant mass with sensation of pressure

    • Small, stable, non-infected and not compromising tissue viability → no surgical intervention necessary (observation w/ warm compresses to hasten resorption)

  • Expanding hematoma

    • Enlarging ecchymotic fluctuant to firm mass with new onset pain (often throbbing)

    • Medical emergency if expanding hematoma in periorbital and cervical locations

  • If very early hematoma (warm, swollen, fluctuant) → intervention recommended to prevent further progression (same intervention as for expanding hematoma)

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Aug 7, 2017 | Posted by in Dermatology | Comments Off on Dermatologic Surgery
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