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Dental Classifications

i. Tooth Numbering1. The maxillary right first molar is #1 and then continues

count to the left and begins on the left for the mandibular teethii. Definitions

1. Mesial anterior (toward incisors)2. Distal posterior (toward the body/angle)

iii. Angle Classification (occlusion)1. Class I

a. Normal occlusion b. The mesial buccal cusp of the maxillary 1st molar is

in occlusion with the buccal groove of themandibular first molar

2. Class IIa. Retrognathia b. The buccal groove of the mandibular first molar is

distal to the mesial buccal cusp of the maxillary firstmolar

3. Class IIIa. Prognathia b. The buccal groove of the mandibular first molar is

mesial to the buccal cusp of the maxillary firstmolar

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b. Mandible Fractures

i. Midface Buttress System1. Function

a. Resist masticatory forces2. Types

a. Nasomaxillary (NM) b. Zygomaticomaxillary (ZM)

i. Carries the GREATEST occlusal loadii. V-shaped bone

c. Pterygomaxillary (PM)d. Nasal Septum

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b. Le Fort fracturesi. Types

1. Ia. Transverse maxillary fracture to the pterygoid plates b. Alveolar separation

2. IIa. Nasofrontal suture, orbital rim or floor b. Pterygoid plate, ZM suture

3. IIIa. Craniofacial disassociation b. Separates the face from the skull basec. Le Fort II with lateral extension

i. Lateral orbital wallii. Zygoma

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CH 121 Facial Analysis

I. General Principlesa. Facial Landmarks

i. Trichion

1. Superior forehead margin at the hairlineii. Glabella1. Superior bony prominence of the inferior frontal bone2. The most prominent point on lateral view

iii. Radix1. Root of the nose2. Includes the following structures:

a. Nasofrontal Angle (NFA)b. Sellion

i. Deepest portion (point) of the nasofrontalangle

c. Nasioni. Bony landmark of the frontonasal sutureiv. Rhinion

1. The bony-cartilagenous junction of the nasal dorsum2. The keystone3. May be up to 11 mm long4. The maximal dorsal prominence5. Has the thinnest skin

v. Tip-defining point1. Anterior most projection of the nasal tip2. The dome or lateral genu of the lower lateral cartilages

a. Represents the apex of the alar cartilagevi. Supratip Break 1. Mild depression superior to the tip

vii. Collumellar Point1. Anterior most point of the columella

viii. Infratip Break 1. Formed by the nasolabial angle2. At the junction of the medial crura & the intermediate crura

ix. Subnasale1. Junction of upper lip and columella

x. Alar Crease

xi. Superior & Inferior Vermelion1. Mucocutaneous junction of the upper & lower lidxii. Stomion

1. Embrasure (contact point) of the lipsxiii. Mentolabial Sulcus

1. Depression between the lower lip an chinxiv. Pogonion

1. Most prominent anterior projection of the chin

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xv. Menton1. Lowest soft tissue border of the chin

xvi. Gnathion1. Projected point at the intersection of the menton and

pogonion

xvii. Cervical Point1. Point at the intersection of the menton and the neck linexviii. Tragion

1. Supratragal notch of the ear

b. Prominent Anglesi. Nasofrontal Angle (NFA)

1. Angle at the nasion2. 115-130 (120)

ii. Nasofacial Angle (NFcA)1. Angle of the nasal dorsum from the face

a. Line drawn from glabella to the pogonion2. 30-40

iii. Nasolabial Angle (NLA)1. 90 to 105 in males2. 100 to 120 in females

iv. Mentocervical Angle (MCA)1. Angle at the gnathion2. 80-90

v. Frankfort horizontal plane1. Line from superior margin of the EAC to the inferior

(bony) border of the infraorbital rim2. Should be parallel to the floor on lateral view

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vi. The intermediate crura forms an angle of 50 to 60 between the tipcartilages

1. Greater angles lead to a boxy or bifid tip

c. Other Parametersi. Facial width to length ratio is 3:4

ii. Anterior facial plane1. Line from the glabella to the pogonion2. Should be strait

a. Women may have slight convexityiii. The face is divided in vertical 1/5s

1. Equal to 1 eye widthiv. Horizontal 1/3s

1. Trichion to the glabella2. Glabella to the subnasale3. Subnasale to the menton

a. Divided in to 1/3s at the stomioni. The upper lip length is 1/3

ii. The lower lip and chin are 2/3

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II. Facial Regions

a. Foreheadi. Males have more prominent supraorbital bossingii. Females have a gradual curvature

iii. Deepening the NFA will increase nasal projection b. Eyes

i. Intercanthal distance (ICD) = 1 eyeii. Intercanthal distance = the interpupillary distance (IPD)

1. ICD is 30-35 mm2. IPD is 60-70 mm

iii. Brow1. The brow is more arched and above the supraorbital rim

2. The brow is directly over or inferior to the supraorbitalrim3. The medial & lateral ends form a horizontal line

a. Medial begins at the lateral alar crease/medialcanthus

4. The maximal arch is at the lateral limbus of the irisiv. Eyelid

1. Margin to Reflex Distance (MRD) is the distance from theupper limbus of the iris to the pupil light reflex

a. MRD1 is for the upper lid b. MRD2 is for the lower lid

2. The UL covers 0.5-2 mm of the upper irisa. The iris is 11 mm (5.5 to the light reflex)3. The LL is within 1-2 mm of the inferior limbus4. The UL distance is 7-15 mm from the crease to the lash line5. Ptosis

a. Mild is 1-2 mm (1.5-2.5 mm above the pupil) b. Moderate is 2-3 mm (1.5-0.5 mm above the pupil)c. Severe is > 4 mm (bellow the pupil)

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6. Levator Functiona. Good is > 11 mm b. Moderate is 5-10 mmc. Poor is 0-5 mm

c. Nosei. Nasal width

1. 70% of nasal lengtha. Nasion to tip-defining point

2. Wider for Asian and African Americans3. Approximately equal to the intercanthal distance

ii. The rhinion has a slight dorsal prominenceiii. Tip rotation is the inclination of the NLAiv. Length is the nasion to tip-defining pointv. Projection

1. Protrusion of the tip from the anterior nasal plane2. Many methods to measure

a. Simonsi. The ratio of the distance from the tip-

defining point to the subnasale and liplength is 1:1

b. Goodesi. The ratio of the distance from the alar grove

to the tip-defining point to the nasal length(nasion to the alar grove)

ii. The ideal ratio is 0.55-0.6:1c. Powell & Humphries

i. The ratio of tip projection to nasal height1. Height is the distance from the

nasion to the subnasale

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2. Projection is the distance from a perpendicular line from tip-defining point to the nasal height line

ii. The ideal ratio is 2.8:1d. Projection can indirectly be measured by the

nasofacial angle (NFcA)i. Ideal is 36e. Crumleys

i. 3:4:5 triangle1. The 5 is the distance from the nasion

to the tip defining point2. The 4 is the distance from the nasion

to the alar crease3. The 3 is the distance from the tip

defining point to the 4 line(perpendicular)

ii. 3/5 the length of the nasion to tip defining pointvi. Nasal Base

1. The lobule is the tip above the nostril apices2. The columella-to-lobule ratio is 2:1

a. Divided into 1/3s3. The ala-to-lobule ratio is 1:1 (AP View)4. 2-4 mm of columellar show is normal

d. Malar Regioni. The face is widest at the zygomatic arches

ii. Within the area of:1. Nasal alae to the tragus2. Oral commissure to the lateral canthus

e. Chin & Neck

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1. Detects deblocking from the nerve if muscle activity is present

2. The presence of active motor units in < 14 days is a GOOD prognostic factor with expected rapid recovery

a. The absence of potentials CONFIRMS degeneration

b. Less than 50% recovery2. Electromyography (EMG)a. Deinnervations

i. Fibrilation potentialsii. Appears in 2-3 weeks

b. Reinnervationi. Polysynaptic potentials

c. Voluntary motor potentials indicate at least partially intact nerved. Patterns

i. Myopathy1. Normal frequency & decreased amplitude

ii. Neuropathy1. Decreased frequency & normal amplitude3. Recovery

a. Poor prognosis if > 90% degeneration in 2 weeks with absence of voluntary potentials on EMG

i. Indication for surgical decompressionii. Best recovery if within 2 weeks of injury

b. Good prognosis if stapedial reflex is intact or if returns in 21 daysc. Surgical exploration with repair of nerve disruption is best performed

within 48-72 hrs of injury4. Gullian-Barre is the #1 cause of bilateral CN VII paralysis

SUNDERLAND CNVII TRAUMA SCALE

1 Neuropraxia Neuronal blockage due to increased pressure with completerecovery.

2 Axonotmesis Axonal disruption due to obstructed vascular flow to axon withintact Endoneurium. Distal walerian degenerationSchwann Cell Sheath is intact but axon must re-grow.Good to complete recovery.

3 Neurotmesis Axon, mylin & Endoneurium disruption with Distal walerianDegeneration.

Schwann cell disruption with incomplete recovery and Synkinesis.4 Partial TransectionDisrupt endoneural tubes and perineurium with poor recovery andSynkinesis.

5 Complete Transection No recovery

* Endoneural tubules provide the scaffold for nerve regeneration (worse/incompleterecovery if disrupted).

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Fitzpatrick Skin Scale

I Fair skin/ severe burns (never Tans) II Fair skin/ easy burns (Usually burns, tans with great difficulty)III Light skin/ tans & less burns (AVG tan, Mild Burn)IV Brown Skin/ easily tans (Rare Burn)V Black skin/always tans ((very rarely Burns)VI Darkest black (Never Burns)

Nasal Tip Supports

I MAJOR 1. Scroll Area (Attachments of the upper (ULC) and Lower lateral Cartilages(LLC)2. Caudal Septum (Attachment to Medial Crura)3. Size, Shape, Resiliency & strength of the LLC, medial crura and caudal septum

II MINOR 1. Interdomal ligaments 4. Sesamoid Complex of LLC2. Cartilaginous Dorsal Septum 5. Anterior Nasal Spine3. LLC attachments to Skin 6. Membranous Septum

(skin soft tissue envelope)

Scalp layers

1. Skin2. SC Fat

3. Galea = Frontalis = Sup. Temporal Fascia = Temporopariental Fascia = SMAS =Platysma4. Loose CT = Parietomaseteric fascia5. Pericranium = deep temporal fascia* CN VII runs between 3 and 4, these layers fuse at the zygoma and CNVII runs in the superficial temporal fascia (#3) This is CRITICAL toknow and gets pimped often!!!!!!!!

Audiology

1. Basic Audiologya. Pure tone average (PTA) is AVG of thresholds at 500, 1000 & 2000Hz b. Speech reception threshold (SRT) is the lowest dB Pt. can repeat 2-

syllable (spondaic) words 50% of the timec. Speech discrimination testing (SDT) is the % of single-syllable words

repeated.d. Crossover occurs at 40dB (AC)e. Maximal CHL is 60dB (Intact TM with Ossicular discontinuity)

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i. 45dB with TM Perforation & INTACT ossiclesf. Fork tests results

i. AC>BC at 512, 1024, BC>AC @256: 20-30dB CHLii. AC>BC at1024, BC>AC at 256, 512: 30-45dB CHL

iii. BC>AC @256,512, 1024 Hz: 45-60dB CHL

g. Rollover is discrimination with signal intensityi. Retrocochlear pathologyh. As Tympanogram is shallow peak c/w otosclerosis or tympanosclerosisi. Ad Tympanogram is high peak c/w ossicular discontinuity

2. Notchesa. Carharts: Notch at 2000Hz in otosclerosis b. Biolermaker Notch: 4000Hz notch in noise induced HL

i. Maximal loss of noise induced HLc. Cookie bite (U shape) notch in hereditary HL

3. ABR:a. Normal wave I indicates normal cochlea in hearing screen

b. Wave V latency difference > 0.2 msec is suggestive of retrocochlear pathologyc. Detectable at 28 weeks gestation

4. Pediatric Audiologya. Behavioral observational Audiometry (BOA) (0-5 months) b. Visual Reinforcement (6-24 Months)c. Transient operant conditioning audiometry (TROCA) (2-3 years)d. Play Audiometry (2-5 Years)e. Conventional Audiometry (> 5 Years)