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Home , Angular artery, Buccal artery, Dorsal nasal artery, Facial artery, Inferior labial artery, Infraorbital artery

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

Introduction the underlying musculature connects to the galea apone- urotica. Muscles of the and include fron- Knowledge of anatomy is essential to every surgeon. The talis, temporalis, procerus, corrugator supercilii, and subtleties of surface anatomy require a special, fi ne - tuned superior fi bers of the orbicularis oculi (Figure 1.1 a). understanding and are meaningful for a successful der- Deep to the aponeurotic layer is the loose connective matologic procedure in both cutaneous oncology and tissue that is largely avascular but does contain perforat- cosmetic surgery. Understanding the cutaneous anatomy ing emissary . Lastly, the envelops the of the head and is essential in directing appropriate bony and contains another layer of vasculature. anesthesia, reducing postoperative complications, and providing for an acceptable cosmetic outcome. The Vasculature anatomy of the is often regarded in terms of cosmetic The blood supply to the forehead and scalp subunits is subunits and will be discussed as such in this chapter. provided by branches of both the internal and the exter- nal carotid . The supratrochlear and supraorbital arteries supply the central forehead and anterior scalp Scalp and forehead and originate from the ophthalmic branch of the internal carotid (Figure 1.1 b). The lateral forehead and The frontal hairline separates the forehead from the scalp scalp are supplied by the superfi cial temporal and poste- superiorly and laterally, and the temporal region is sepa- rior auricular branches of the rated from the scalp by the temporal hairline. 1 The fore- (Figure 1.1 c). The posterior scalp is supplied by the head ends at the zygomatic arch inferiorly, while the , another branch of the external carotid inferior scalp is separated from the neck by the nuchal (Figure 1.1 c). 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 The motor and sensory anatomy of the forehead and connective tissue, and p eriosteum. In its most anterior scalp are a crucial part of surgery on these subunits. segment, the skin of the scalp measures about 3 – 4 mm in Motor innervation of the forehead is provided by the thickness and reaches up to 8 mm in the more posterior temporal branch of the facial (CN VII). This segments. Blood vessels, lymphatics, and cutaneous branch runs along the and the zygomatic arch adnexa reside within the connective tissue layers, while but courses more superfi cially superiorly to innervate the

Dermatologic Surgery: Step by Step, First Edition. Edited by Keyvan Nouri. © 2013 Blackwell Publishing Ltd. Published 2013 by Blackwell Publishing Ltd.

3 4 PART 1: Dermatologic Surgery

(a)

Supratrochlear nerve Deep branch, Supraorbital nerve Corrugator supercilii muscle Depressor supercilii muscle Temporal branches Zygomatic Infratrochlear nerve

(b)

Supratrochlear artery

Supraorbital artery Frontal branch of superficial temporal artery Zygomatico-orbital artery Deep temporal artery

External nasal artery Transverse

Buccal artery

Facial artery Mental artery

Submental 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

(c) Frontal branch of superficial temporal artery Branches of the Supratrochlear artery Parietal branch of superficial temporal artery Superficial temporal artery Deep temporal artery

Occipital artery Internal Posterior auricular artery

External carotid artery

Figure 1.1 (Continued) frontalis muscle at its deep surface. It is therefore most sidewall, nasal dorsum, tip, alae, soft triangles, and the susceptible to injury at its superfi cial course, which may columella (Figure 1.3 a). To achieve the best cosmetic result in ipsilateral brow ptosis and pronounced asym- outcome, it is recommended that incision lines during metry of the face (Figure 1.1 a). nasal reconstruction are placed at the borders of these The sensory innervation of the forehead and scalp is cosmetic units. The nasal cartilaginous structures, con- provided by branches of all three divisions of the trigemi- sisting of the lateral nasal and the lower lateral cartilage, nal nerve (CN V). The supraorbital and supratrochlear are essential to the integrity of the nose (Figure 1.3 a). nerves branch off from the ophthalmic nerve (CNV1) to Certain infi ltrative tumors may infi ltrate the lower lateral supply the scalp up to the vertex (Figure 1.1 a). The zygo- nasal cartilage, requiring its excision. Failure to properly maticotemporal nerve, arising from the maxillary divi- repair the cartilage in this situation may result in the loss sion of the trigeminal nerve (CN V2), supplies sensory of alar support leading to collapse of the nasal ala and innervations to the anterior temple. The auriculotempo- inhibition of air fl ow into the nose. ral nerve, a branch of the mandibular division (CN V3), supplies the rest of the temporal area. Branches of the Vasculature cervical spinal nerves (C2, C3) innervate the posterior Similar to the forehead and scalp region, the vasculature scalp. of the nose is derived from both the internal and external carotid arteries.3 In fact, arteries supplying the nasal area Lymphatic drainage make up one of the essential anastomosing sites between The lymphatic drainage of the scalp is collected by the the internal and external carotid arteries. The dorsal nasal occipital and posterior auricular lymph nodes (Figure and external nasal branches of the , 1.2 ). The basin responsible for lymph drainage of the which branches off from the external carotid, supply the forehead subunit is located within the parotid glands dorsal nose (Figure 1.3 b). Vascular supply to the nasal bilaterally. 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 Mid-face (Figure 1.3 b).

Nasal subunit Nerves The nasal subunit is generally further subdivided into a Motor innervations to the procerus muscle at the number of cosmetic subunits. 2 These consist of the nasal nasal root, depressor septi nasi and nasalis muscles are 6 PART 1: Dermatologic Surgery

Malar node Facial nodes Infraorbital node Pre-auricular nodes Buccinator node Post-auricular nodes Occipital nodes Mandibular nodes Submental nodes Parotid nodes Submandibular nodes Spinal accessory chain Superficial cervical node Internal jugular chain Transverse cervical chain

Figure 1.2 Lymphatic drainage of the head and neck.

provided by the zygomatic and buccal branches of the Vasculature facial nerve (CN VII) (Figure 1.4 ). The ophthalmic and Vascular supply to the is provided by the labial arter- maxillary divisions of the trigeminal nerve provide ies that branch off the facial artery. Labial arteries are sensory innervation to the nose. The infratrochlear and frequently resected during biopsies and surgery. Intra- external nasal branches of the ophthalmic division (CN operative ligation or electrosurgery is usually suffi cient to V1) and the infraorbital branch of the maxillary division prevent excessive bleeding. (CN V2) are the primary sources of sensory innervation for this subunit. Nerves Perioral musculature is innervated by the zygomatic, Lymphatic drainage buccal, marginal mandibular, and cervical branches of Lymphatic drainage from the nose is collected primarily the facial nerve (CN VII) (Figure 1.4 ). The maxillary by the submandibular lymph nodes (Figure 1.2 ). division (CN V2) provides sensory innervations to the upper perioral region via the . The mandibular division (CN V3) contributes to the sensory Perioral innervation of the lower lip via the mental nerve.

The surface anatomy of the lip is divided into the lateral Lymphatic drainage wings of the cutaneous upper lip, philtrum, lower lip and The primary site of lymphatic drainage from the perioral the vermillion border which demarcates the red and region is the submental lymph nodes (Figure 1.2 ). white portion of the lips (Figure 1.5 a). 4 The underlying musculature includes the orbicularis oris, zygomaticus major and minor, , depressor anguli Chin oris, , depressor labii inferioris, , , and the buccinators (Figure 1.5 b). The The cosmetic subunit of the chin is demarcated from the nasolabial crease is formed by the cutaneous insertion of and lip subunits by the mentolabial crease. Sur- lip elevator musculature. geons must be aware of the location of the mental CHAPTER 1: Cutaneous anatomy in dermatologic surgery 7

(a)

Sidewall Dorsum Supratip Tip Lobule Ala Infratip Columella Soft triangle Alar margin

(b)

Infratrochlear/ dorsal nasal artery Infratrochlear nerve Infraorbital External nasal artery and artery and nerve nerve

Transverse Lateral nasal facial artery artery Angular artery

Superior labial Facial artery artery

Figure 1.3 (a) Landmarks in nasal anatomy; (b) nasal vasculature and sensory nerves. foramen that carries the mental nerve and vessels to the Nerves chin, and is located below the second mandibular premo- Motor innervation to the chin is provided by the mar- lar tooth in the majority of the population. Musculature ginal mandibular branch of the facial nerve (CN VII). of the chin consists of the mentalis, depressor anguli oris, Injury to this nerve may occur as it crosses the and depressor labii inferioris (Figure 1.5 b). at the medial edge of the within the superfi cial soft tissue (Figure 1.4 ). Marginal mandibular Vasculature injury is manifested as ipsilateral asymmetry of the lip The mental and submental arteries branch off the and chin during smiling. The mental nerve, entering via external carotid artery to form the vascular supply of the mental foramen, provides the sensory innervation to the chin. the chin subunit. 8 PART 1: Dermatologic Surgery

Branches of facial nerve

Temporal

Zygomatic

Buccal

Marginal mandibular Facial nerve Cervical

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

Lymphatic drainage branch of the internal carotid system anastomoses with The submental lymph node basin collects lymphatic the angular branch of the facial artery in the vicinity drainage from the chin subunit (Figure 1.2 ). of the medial canthus (Figure 1.6 b). Supraorbital and supratrochlear artery branches of the internal carotid system also supply the upper area (Figure 1.6 b). Periorbital The external carotid artery supplies vasculature to the lower eyelid by the infraorbital branch of the maxillary An understanding of periorbital anatomy is key to avoid- artery and to the lateral periorbital area via the superfi cial ance of ectropion and entropion complications of cuta- temporal artery. neous surgery in this region. The are made up of the skin, orbicularis oculi muscle, the tarsus, and the Nerves .5 Overall structural support to the eyelids is Knowledge of neural anatomy of the periocular region is provided by the medial and lateral canthal . The crucial both to proper anesthesia and to botulinum toxin superior and inferior lacrimal canaliculi are enveloped by treatment of the motor component of the eyelid region. the medial canthal and are the means of passage Sensory innervation is provided by the ophthalmic divi- of tears to the . Disruption of the canaliculi sion (CN V1). The is innervated by the supratro- will lead to a defect in tear drainage. Glands of Zeis and chlear branch of the ophthalmic division. Sensation to meibomian glands are large sebaceous glands that reside the lower eyelid is mediated by the infraorbital nerve. The in the eyelids (Figure 1.6 a). Glands of Moll are apocrine zygomatic branch of the facial nerve (CN VII) provides glands of the eyelids (Figure 1.6 a). motor innervations to the orbicularis oculi, levator palpebrae superioris, and parts of the procerus muscles Vasculature (Figure 1.4 ). The temporal branch of facial nerve is The internal and external carotid arteries provide a vas- responsible for motor innervations of the corrugators cular supply to the periorbital area. The dorsal nasal and procerus. CHAPTER 1: Cutaneous anatomy in dermatologic surgery 9

(a)

Philtrum Cutaneoous upper lip Labial tubercle Vermillion border Labial Labiomental commissure groove Oral fissure

(b) Superficial Deep

Levator labi superioris alaeque nasi muscle Levator labi superioris muscle Levator angularis oris muscle Infraorbital nerve

Facial nerve, zygomatic branches Mental nerve Depressor labi inferioris muscle Risorius muscle Mental muscle Depressor anguli oris muscle

Platysma muscle

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

Lymphatic drainage subdivided into the medial, zygomatic, buccal, and lateral The lymphatic drainage basin of the lateral eyelid area cheek units. Each of these has unique surface charac- lies primarily within the parotid lymph nodes. Medial teristics and sebaceous nature that must be taken into canthus lymph drains to the submandibular lymph node account during reconstruction.6 basin.

Vasculature Vasculature supplying the cheek subunit is derived from the external carotid artery system. The transverse facial The cheek is the largest facial subunit. Its superior border artery supplies the lateral cheek. The angular branch of is made of the infraorbital rim and zygomatic arch. the facial artery and the infraorbital artery supply the The nasolabial and melolabial folds mark the medial medial aspects of the cheeks (Figure 1.1 b). Multiple anas- border and the pre - auricular crease makes up the lateral tomotic connections within the cheek make this subunit border of the cheek. The cheek subunit can be further a highly vascularized skin surface. 10 PART 1: Dermatologic Surgery

(a) Medial fat pad Preaponeurotic Trochlear fat pad Superior lacrimal Orbital part of papila and puncta Lacrimal sac Palpebral part of Lacrimal caruncle lacrimal gland Pilca semilunaris Temporal fat pad Lacrimal canaliculi Inferior oblique Inferior lacrimal muscle papilla and puncta Medial fat pad Nasolacrimal duct

(b) Superior orbital artery Frontal branch of superficial temporal artery Supratrochlear artery Superior palpebral artery Dorsal nasal artery

Superior/inferior palpebral artery Zygomaticocorbital artery Angular artery Infraorbital artery

Transverse facial artery

Facial artery

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

Nerves of the cheek subunit. The The muscles of the cheek are supplied with motor inner- innervates parts of the lateral cheek with the buccal vation by the zygomatic and buccal branches of the nerve providing sensation to the lateral and buccal facial nerve (CN VII) (Figure 1.4 ). The infraorbital, portions. The mental nerve innervates the inferior zygomaticofacial, and zygomaticotemporal branches of medial aspects. the maxillary division of the trigeminal nerve supply sensation to the medial and zygomatic aspects of the Lymphatic drainage cheek. Nerves emanating from the mandibular division The parotid and submandibular nodes collect the lym- of the trigeminal nerve provide sensation to the rest phatic drainage from the cheek subunit. CHAPTER 1: Cutaneous anatomy in dermatologic surgery 11

(a) Helix

Triangular Tubercle (of Darwin) Crura of antihelix Scaphoid Root of fossa antihelix Antihelix Tragus

Antitragus Cymba Concha Intertragic Cavum notch

Lobule

(b) Auriculotemporal nerve Lessor occipital nerve

Cranial nerve IX and X

Great auricular nerve

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

Auricular posterior auricular artery. The anterior auricular artery, which branches off from the superfi cial temporal artery, The surface anatomy of the ear is complex, with inter- supplies the anterior ear. mixing of multiple convex and concave surfaces.7 Notable anatomic landmarks of the ear include the helix, crura, Nerves scaphoid fossa, triangular fossa, conchal bowl, antihelix, Sensory innervation of the ear is complex, with the great tragus, antitragus, and lobule (Figure 1.7 a). The auricular auricular nerve (C2, C3) innervating the lower part of the cartilage is found in the upper two- thirds of the ear. lateral and posterior ear. The auriculotemporal branch (CN V3) innervates the superior lateral ear, and the lesser Vasculature occipital nerve provides sensation to the superior poste- Blood supply to the is derived entirely from the rior ear. The external auditory meatus and conchal bowl external carotid artery system.8 The lobule and posterior are supplied by fi bers of the glossopharyngeal (CN IX), ear are supplied by the occipital and posterior auricular auricular branch of the vagus (CN X or Arnold ’ s nerve), arteries. The conchal bowl is supplied by branches of the and facial (CN VII) nerves (Figure 1.7 b). 12 PART 1: Dermatologic Surgery

(a)

Submaxillary triangle Sternocleidomastoid Submental triangle muscle

Superior Posterior triangle Inferior carotid triangle Omoclavicular triangle

Occipital triangle

(b)

Lesser occipital nerve (C2, C3) Greater auricular nerve (C3, C4) (CN XI) Transverse cervical nerve External jugular (C2, C3) Erb’s point Sternocleidomastoid muscle Supraclavicular nerve (C3, C4) muscle

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

Lymphatic drainage identify important underlying structures (Figure 1.8 a). The posterior aspect of the ear drains to the occipital and The superfi cial musculoaponeurotic system (SMAS) is a posterior auricular lymph nodes. Anterior ear lymphatic fi brous layer of that envelops the platysma and the drainage proceeds to the parotid nodes. superfi cial . 9 The easily identifi ed sterno- cleidomastoid muscle separates the anterior and poste- rior triangles of the neck. The posterior triangle contains Neck Erb’ s point, a landmark of the exit of the spinal accessory (CN XI), lesser occipital, and great auricular nerves as The superfi cial anatomy of the neck requires anatomic well the transverse cervical rami (Figure 1.8 b). Damage landmarks indicated by the triangles of the neck to help to the spinal accessory nerve may result in the inability CHAPTER 1: Cutaneous anatomy in dermatologic surgery 13 to raise the ipsilateral shoulder. The jugular and carotid 2. Burget GC , Menick FJ . The subunit principle in nasal recon- vessels run through the carotid triangle (Figure 1.8 a). The struction. Plast Reconstr Surg 1985 ; 76 : 239 – 47 . mental lymph node basin and lingual arteries occupy the 3. Oneal RM , Beil RJ . Surgical anatomy of the nose. Clin Plast submental triangle. The submaxillary triangle includes Surg 2010 ; 37 : 191 – 211 . the , artery, and vein, and . 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 Nerves 2008 ; 10 : 9 – 19 . The cervical branch of the facial nerve (CN VII) provides 5. Most SP , Mobley SR , Larrabee WF , Jr . Anatomy of the eyelids. the motor innervation to the platysma. Sensory innerva- Facial Plast Surg Clin North Am 2005 ; 13 : 487 – 92 , v. tion to this area is provided by the transverse cervical, 6. Dobratz EJ , Hilger PA . Cheek defects . Facial Plast Surg Clin supraclavicular, and great auricular nerves. North Am 2009 ; 17 : 455 – 67 . 7. Shonka DC , Jr ., Park SS . Ear defects. Facial Plast Surg Clin Lymphatic drainage North Am 2009 ; 17 : 429 – 43 . Lymphatic nodes of the neck region are the secondary 8. Park C , Lineaweaver WC , Rumly TO , Buncke HJ . Arterial lymph nodes that receive drainage from most nodes on supply of the anterior ear. Plast Reconstr Surg 1992 ; 90 : the face. These eventually empty into the venous circula- 38 – 44 . 9. Mitz V , Peyronie M . The superfi cial musculo- aponeurotic tion via the thoracic duct. system (SMAS) in the parotid and cheek area. Plast Reconstr Surg 1976 ; 58 : 80 – 8 . 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 .