Facial Proportions and Subunits

Facial Proportions and Subunits

Canon 1. The head-face height is in two equal parts. Vertex – endocanthion – gnathion

Canon 2. Combined forehead – face height is in three equal parts. Trichion(hairline) – nasion(glabella) – subnasale – gnathion

Canon 3. Combined head – face height is divided into four equal parts. Vertex – trichion – nasion/glabella – subnasale – gnathion.

Canon 4. Length of the nose equals the length of the ear.

Canon 5. Interocular distance equals the width of the nose.

Canon 6. Interocular distance equals the length of the orbital fissure.

Canon 7. Width of the mouth is 1.5 times width of the nose.

Canon 8. Width of the nose and eye is 1/5 the width of the face.

Canon 9. The inclination of the nasal bridge parallels the long medial axis of the ear.

not entirely accurate (Farkas)

1.Vx—endocanthion distance> endocanthion—gnathioin distance in most

2. Nasion—subnasale < Trichion—nasion and Nasion—subnasale < subnasale—gnathion

3. gnathion—subnasale > subnasale—glabella > trichion—vertex > trichion—glabella

4. nose length < ear length

5. interoccular distance < nasal width (alar) in 1/3 and > in 1/5

6. interoccular distance > palpebral fissure in most

7. width of mouth is > 1.5x width nose in 60%

8. width of nose < or > ¼ width of face in most

9. inclination of nasal bridge exceeds tilt of medial axis ear in most

The canon face is different to the modern face, especially in the forehead.

Brachycephalic – short and wide

Dolichocephalic – long and narrow

Mesocephalic – medium length and width

Ear

· The vertical axis of the ear should be inclined 20° anteriorly.

· The ear is positioned 1 ear length (60-65mm) posterior to the lateral orbital rim between eyebrow and columella

· The width of the ear should be 55% of the height (35mm).

· The helix should be visible on the frontal view 2-5mm laterally behind the antihelix.

· The helical rim should be symmetrically located to within 15-20mm of the scalp with an auriculocephalic angle of protrusion of 25-35°.

· Conchalscaphal angle 75-105°.

Forehead

· Note excessive glabellar prominence and supraorbital ridge projection. Treat with bone reduction with or without entry into sinus and augmentation of cavity above the bossing.

· Brow rhytides – fine, heavy or secondary to animation

· Brow position

o Ideally 20-25mm above upper lid margin when eye is closed

o Medial end of eyebrow is just caudal to lateral end which sits on the supraorbital bar

o Highest portion is at the junction of the lateral 1/3 to medial 2/3 – corresponds to lateral limbus

Eyes

· Fissure height 10mm

· Cornea 2-3mm anterior to the inferior rim.

· Highest point of upper lid is junction medial and middle third, lowest point of lower lid is central to lateral thirds.

· Upper lid sits <2cm below upper limbus.

· Margin crease distance (MCD) is the distance from the upper eyelid margin to the lid crease. In white women - 10-11 mm and in white men, 8-10 mm.

· normal inter-orbital distance is 25 mm in women and 28 mm in men. Marked racial differences

· Classification of hypertelorism

o Tessier - interdacryon distance measured on a frontal cephalogram

1. grade 1 = 30 to 34 mm

2. grade 2 = 35 to 39 mm

3. grade 3 = >40 mm

o Mulliken -classification based on the standard deviation (SD) of the interdacryon distance

1. grade 1 = +2 to 4 SD

2. grade 2 = +4 to 8 SD

3. grade 3 = >+8 SD.

· Classification of lid excursion

1. poor <4cm

2. fair 4-7cm

3. Good 8-10cm

4. Normal 11-15cm

· Classification of Ptosis

o Based on upper lid relation to upper limbus. Iris is 10mm

1. Mild 1-2mm

2. Moderate 3mm

3. Severe >4cm

o Marginal reflex distance -1 (MRD-1). Distance from light reflex to upper lid margin, should be 4mm

o Marginal reflex distance -2 (MRD-2). Distance from light reflex to lower lid margin, should be 5mm

Nose

· projection angle 30-36deg.

· Nasofrontal angle lies at supratarsal fold level.

· Nasal length equals stomion to menton (2/3 of middle third)

· Nasal tip projection is 2/3 ideal nasal length

· 50-60% of nasal height should lie anterior to the most projecting part of upper lip

· Nasal dorsum is outlined by 2 slightly curved divergent lines extending from medial brow to tip defining points

· Bony base should be ¾ of alar base

· Width of alar base=intercanthal distance=width of 1 eye

· Lines connecting the 2 tip defining points, supratip break and alar-columella-lobular angle form 2 equilateral triangles.

· Columella-labial angle 95-105° in male, 105-115° in female.

· 2-3mm columella show below the alar rim on lateral

Mouth

· Base of nose to inferior border of upper lip is 1/3 of the lower third of the face. Lower two thirds extends from this to the chin.

· Vermillion border of the lower lip is midway between the base of the nose and the chin.

· The corners of the mouth halfway between the alar base and pupil. Lower lip 2mm posterior to a line from chin to tip of nose, upper lip 4mm posterior.

Chin

in both men and women, the chin rests slightly posterior to the lower lip and the lower lip lies slightly posterior to the upper lip.

· In the “normal” lip position on AP, the commissures lie between the pupils

· In profile the lips should be slightly parted and the lower lip should lie only just posterior to the upper lip.

· upper lip ideally covers two thirds of the incisors.