30 - 201 - CUTANEOUS SURGICAL ANATOMY

Question 1

fibromuscular layer connecting the facial muscles

Answer 1

superficial musculoaponeurotic system (SMAS)

Question 2

ideal location of undermining in relation to SMAS

Answer 2

Incisions and undermining within the subcutaneous fat above SMAS will not result in damage to motor nerves

• The SMAS is an important landmark because most major arteries and nerves run within or deep to it.
• Dissection above the SMAS allows the dermatologic surgeon to safely avoid neurovascular structures.

Question 3

provide sensory innervation to the face

Answer 3

three branches of the trigeminal nerve (cranial nerve V)

Question 4

three main danger zones

Answer 4

• areas where the temporal and marginal mandibular branches of the facial nerve and** spinal accessory nerve** lie superficial and can be easily injured

Question 5

result of damage to the temporal branch of the facial nerve

Answer 5

ipsilateral eyebrow ptosis and obscuring of the superolateral visual field

Question 6

marginal mandibular branch of the facial nerve is vulnerable to damage where?

Answer 6

along the inferior edge of the body of the mandible

Question 7

Damage to the marginal mandibular branch of the facial nerve will result in what?

Answer 7

asymmetrical smile

Question 8

landmark for the spinal accessory nerve

Answer 8

posterior triangle of the neck and may be identified by Erb’s point

Question 9

borders of SMAS

Answer 9

• Above: temporalis and frontalis muscles
• Below: platysma
• Anterior orbicularis oculi
• Posterior: trapezius

Question 10

Cosmetic units are zones of tissue that share cutaneous features such as..

Answer 10

color, texture, pilosebaceous quality, pore size, and degree of actinic exposure

Question 11

represent the major cosmetic units of the face.

Answer 11

forehead, temples, eyelids, nose, cheeks, upper and lower lips, chin, and ears

Question 12

the area between the eyebrows

Answer 12

glabella

Question 13

the deep sulcus below the glabella and uppermost portion of the nose

Answer 13

root of the nose

Question 14

the area overlying the nasal bone

Answer 14

dorsum or bridge

Question 15

the sides of the nose

Answer 15

lateral sidewalls

Question 16

the nostril

Answer 16

nasal ala

Question 17

the grooves that demarcate the alae superiorly from the lateral nasal sidewall and alae inferiorly from the lip, respectively

Answer 17

nasolabial crease

Question 18

the mobile linear structure separating the alae inferiorly

Answer 18

columella

Question 19

The central concavity within which the external auditory meatus lies

Answer 19

concha

Question 20

lateral surface of the ear is rimmed by what part of the ear?

Answer 20

helix

a curved cartilaginous structure that begins at the crus just above the external auditory canal and continues around the ear to end at the fleshy lobule

Question 21

superior and inferior portion of the concha

Answer 21

The concha is divided by the crus of the helix into a superior portion; the cymba; and an inferior portion, the cavum.

Question 22

he posterior border of the concha is formed by another cartilaginous structure

Answer 22

antihelix

Superiorly, the antihelix originates from two legs (crus is Latin for leg): (1) the superior crus and (2) inferior crus.

Question 23

region between the crura

Answer 23

triangular fossa

Question 24

groove between the helix and antihelix

Answer 24

scaphoid fossa

Question 25

triangulated cartilaginous structure just anterior to the auditory canal

Answer 25

tragus

Question 26

triangulated end of the antihelix

Answer 26

antitragus

Question 27

The inferior region between the tragus and antitragus

Answer 27

intertragic notch

Question 28

cutaneous upper lip has a concave depression in the center

Answer 28

philtrum

Question 29

divides the cutaneous lower lip from the chin

Answer 29

mental crease

Question 30

boundary between the red mucosal surface of the lips and the cutaneous surface

Answer 30

vermillion border

Question 31

raised contoured area of the inferior portion of the philtrum is a critical aesthetic landmark

Answer 31

Cupid’s bow

Question 32

any anatomical structure that can be easily distorted when tension is placed on it

Answer 32

free margin ## Footnote * When these regions become distorted, the resulting asymmetry can cause cosmetic and functional concerns * An ectropion can result in epiphora, as well as conjunctival and corneal exposure leading to corneal scarring * An eclabium may result in altered speech, an asymmetrical smile, or drooling.

Question 33

what are free margins of the face

Answer 33

eyelid margin, alar rim, lip vermillion, and helical rim

Question 34

another characteristic of the face that help guide surgical reconstruction and allow the structural camouflage of scar lines

Answer 34

RELAXED SKIN TENSION LINES

Question 35

creases on the face that form over time because of factors such as loss of elastic tissue tone, lengthening of the collagenous fibrous septae that connect the dermis to the underlying facial muscles, development of excessive skin, gravity, and ultraviolet radiation exposure

Answer 35

RELAXED SKIN TENSION LINES ## Footnote * RSTLs usually run perpendicular to the underlying muscles. * In most situations, the long axis of the excision should be placed parallel to the RSTL because they are often in the direction of the least tension for a scar.

Question 36

facial nerve location

Answer 36

* The facial nerve exits the skull through the stylomastoid foramen near the earlobe and immediately gives off the posterior auricular branch, which provides motor innervation to the occipital and posterior auricular muscles. * It then enters the parotid gland at the midpoint of a line connecting the tragus with the angle of the mandible. * Within the parotid gland, the facial nerve divides into the temporofacial and cervicofacial rami from which five branches arise. * After leaving the parotid gland, the branches of the facial nerve lie deep to the SMAS and enter the muscles of facial expression from their deep surface. * The branches of the facial nerve are therefore well protected during surgical procedures that are no deeper than fat. * However, it is important to note that there can be minimal thickness of the fat layer at certain sites such as the temple and at other sites in older adult patients.

Question 37

five main branches of facial nerve

Answer 37

(1) temporal, (2) zygomatic, (3) buccal, (4) mandibular, (5) cervical

Question 38

what are the two branches of the facial nerve most susceptible to injury during dermatologic surgery? where are they most susceptible?

Answer 38

* **temporal branch **as it **crosses the zygomatic arch ** * **marginal mandibular branch** along the **inferior border of the mandible**

Question 39

Question 40

location of the Temporal branch of the facial nerve

Answer 40

Facial nerve as it crosses the middle third of the zygomatic arch

Question 41

damage to temporal nerve

Answer 41

* Flattening of forehead, * diminished wrinkles, skin tension lines, * eyebrow and eyelid ptosis, * visual field disturbance

Question 42

location of the marginal branch of the facial nerve

Answer 42

Inferior border of the mandible, as the nerve crosses the angle of the mandible at the inferoanterior border of the masseter

Question 43

damage to the marginal mandibular branch of the facial nerve

Answer 43

Contralateral and upward pull on the mouth; ipsilateral side presents with lip droop

Question 44

location of Spinal accessory nerve

Answer 44

Posterior triangle of the neck, from the midpoint of the posterior border of the sternocleidomastoid

Question 45

damage to spinal accessory nerve

Answer 45

* Paralysis of trapezius, * winging of the scapula, * shoulder drop, * inability to shrug the shoulder, * difficulty with arm abduction, * chronic shoulder pain

Question 45

The approximate course of the temporal branch of the facial nerve can be projected on the skin by what landmark?

Answer 45

earlobe to the lateral edge of the eyebrow and another line from the tragus to just above the and behind the highest forehead crease

Question 46

landmark for Erb's point

Answer 46

* drawing a line connecting the angle of the mandible with the mastoid process * A vertical line is then drawn from the midpoint of this line **6 cm **inferiorly. * The point at which this line intersects the posterior border of the sternocleidomastoid muscle is Erb’s point. ## Footnote * the point at which the spinal accessory nerve emerges from behind the sternocleidomastoid

Question 46

The marginal mandibular branch of the facial nerve exits the parotid gland where?

Answer 46

angle of the jaw ## Footnote * It divides into two or more rami and travels anteriorly along the us of the mandible to supply the **depressor anguli oris, the depressor labii inferioris, the mentalis, and part of the orbicularis oris.** * As it crosses the angle of the mandible at the inferoanterior border of the masseter, the marginal mandibular nerve is covered only by skin, subcutaneous fat, and fascia, which may be thin in this location, particularly in older adults

Question 47

the trigeminal nerve exits the skull via three foramina

Answer 47

supraorbital, infraorbital, and mental foramina ## Footnote located bilaterally in the midpupillary line

Question 48

Branches of the Trigeminal Nerve

Answer 48

Question 49

nerves that innervates the forehead and anterior scalp

Answer 49

Supraorbital (lateral) nerve, Supratrochlear (medial) nerve

Question 50

nerve that innervates the Upper eyelid

Answer 50

Lacrimal nerve

Question 51

innervates the Glabella, nasal root, nose bridge

Answer 51

Infratrochlear nerve (nasociliary)

Question 52

innervates Eyelid, superior cheek

Answer 52

Infraorbital nerve

Question 53

innervates Most of the temple, temporoparietal scalp, anterior ears, external ear canal, tympanic membrane

Answer 53

Auriculotemporal

Question 54

innervates Buccinators, buccal mucosa, gingiva

Answer 54

Buccal nerve

Question 55

innervates Lower lip, chin

Answer 55

mental nerve

Question 56

eyebrows move medially and downward with contraction of what muscles?

Answer 56

corrugator supercilii muscles

Question 57

lies between the supercilii muscles and draws the skin of the forehead inferiorly to create the horizontal creases at the root of the nose

Answer 57

procerus

Question 58

surrounds the eye and consists of an orbital and palpebral portion

Answer 58

orbicularis oculi muscle ## Footnote The orbicularis oculi muscle serves to close the eyes with the palpebral part with both reflexive and voluntary control and the orbital part with voluntary control.

Question 59

central sphincter-like muscle around the mouth

Answer 59

orbicularis oris ## Footnote This muscle helps purse the lips to form certain sounds and whistle

Question 60

lip depressors

Answer 60

depressor anguli oris, depressor labii inferioris, and the mentalis

Question 61

lip elevators

Answer 61

zygomaticus major, zygomatic minor, levator anguli oris, levator labii superioris, and levator superioris alaeque nasi

Question 62

The blood supply of the face is almost entirely derived from branches of what artery?

Answer 62

external carotid artery

Question 63

The continuation of the facial artery in the nasofacial sulcus is called?

Answer 63

angular artery

Question 64

terminal branches of the internal carotid artery

Answer 64

ophthalmic artery branches, the supraorbital artery, and the supratrochlear artery

Question 65

internal and external carotid systems join in two places

Answer 65

(1) where the supratrochlear branch and the dorsal nasal artery anastomose with the angular artery and (2) where the forehead branches of the supraorbital and supratrochlear arteries anastomose with branches of the superficial temporal artery.

Question 66

lymphatic drainage of the face

Answer 66

* posterior scalp - postauricular and occipital nodes * lateral and superior face - forehead * lateral eyelids - parotid nodes * medial and inferior face, including the medial eyelids and lateral lips - submandibular nodes * middle two thirds of the lower lip and the chin - submental nodes