Lateral Cephalometry



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Lateral Cephalometry

A lateral cephalogram is one of the orthodontic records that provides information about the sagittal and vertical relations of:

• The craniofacial skeleton

• The soft tissue profile

• The dentition


• The pharynx

• The cervical vertebrae

These structures and their relationships to each other are inspected by means of linear and angular measurements as well as by the use of ratios based on the various cephalometric landmarks.



Some important landmarks include:

  • Na - nasion - the most anterior point of the frontonasal suture in the median plane

  • S- sella - the point representing the midpoint of the pituitary fossa (sella turcica)

  • A - Point A - the point at the deepest midline concavity on the maxilla between the anterior nasal spine and upper central incisors

  • B - Point B - the point at the deepest midline concavity on the mandibular symphysis between infradentale and pogonion

  • Pog - pogonion - the most anterior point of the bony chin in the median plane

  • Gn - gnathion - the most anteroinferior point on the symphysis of the chin

  • Me- menton - the most inferior midline point on the mandibular symphysis

  • Go-gonion - the constructed point of intersection of the ramus plane and the mandibular plane



  • FH - Frankfort horizontal – (reference line) line connecting the 
points porion (po) and orbitale (or) 








Angles

Mean Values

Increased value interpretation

Decreased value interpretation

1.

NPog-FH

88°

Prognathic face

Retrognathic face

2.

MeGo-FH (Mandibular plane angle)

22°

Hyperdivergent

Hypodivergent

3.

Occ-FH (Occlusal plane orientation)


Occlusal plane tipped downward


Occlusal plane tipped upwards



4.

Yaxis-FH (Y axis-face height and growth direction)

59°

Vertically growing

Horizontally growing

5.

N-A-Pog (Facial convexity)



Concave

face


Convex

face


6.

AB-NPog (Apical base relationship)

-4.5°

Skeletal. Class 3

Skeletal Class 2

7.

1-1 (Interincisal angle)

135°

Retroclined incisors

Proclined incisors

8.

1-Occ (Lower incisor to Occlusal plane)

14.5°

Proclined mand. Incisor to occ. plane


Retorclined mand. Incisor to occ. plane



9.

1-MeGo (Lower incisor to Occlusal plane)

91°

Proclined mand. Incisor to mand. plane


Retroclined mand. Incisor to mand. plane



10.

1-APog (Upper incisor position)

3 mm

Proclined upper incisors


Retroclined upper incisors


Down’s Analysis

Steiner Analysis







Angles

Mean Values

Increased

decreased

1.

SNA (Maxilla position to cranial base)

82°

Maxillary prognathism


Maxillary retrognathism

2.

SNB (Mandible position to the cranial base)

80°

Mandibular prognathism

Mandibular retrognathism



3.

ANB (relation of maxilla and mandible to each other)



Skeletal class 2

Skeletal class 3

4.

1-NA (Maxillary incisor position)

4 mm

Maxillary incisor positioned anteriorly

Maxillary incisor positioned posteriorly

5.

1-NA (Maxillary incisor inclination)

22°

Proclined maxillary incisor


Retroclined maxillary incisor



6.

ī-NB (Mandibular incisor position)

4 mm

Mandibular incisor positioned anteriorly

Mandibular incisor positioned posteriorly

7.

ī-NB (Mandibular incisor inclination)

25°

Proclined mandibular incisor

Retroclined mandibular incisor

8.

Pog-NB (Chin prominence)

3.5 mm

Recessive chin

Prognathic chin

9.

1- (Interincisal angle)

131°

Retroclined incisors

Proclined incisors



10.

SN-Occ (Occlusal plane orientation)

14°

Steep occlusal plane

Flat occlusal plane

11.

SN-GoGn (Mandibular plane angle)

32°

Hyperdivergent/long face

Hypodivergent/ short face


Holdaway Analysis of soft tissues







Angles

Mean Values

Increased

Decreased

1.

Facial Angle (FH-N’Pog’)

90±2°

Prognathsim

Retrognathsim

2.

Nose Prominence Distance measured between the (a) Perpendicular line tangent to SuperiusLabial Sulcus from FH distance to (b) nose tip)

14-24 mm

Prominent nose

Recessive nose

3.

Skeletal Convexity at A-point (Distance measured from A Point to N- Pog line)



Avg= -2 to +2 mm

Mean=0mm


Convex profile

Concave profile

4.

H-Line angle (Angle between H-line &(N’-Pog’)

7-15°

Recessive chin and protrusive lip

Protrusive chin and recessive lip


5.

Soft tissue subnasale to H-line

Avg=5±2 mm

Mean=3-7 mm



Increase in subnasal depth

Decrease in subnasal depth

6.

Superior Sulcus Depth (Depth of sulcus from a line drawn perpendicular to FH and tangent to tip of upper lip.

1-4 mm

Increased in depth


Decreased n depth

7.

Upper lip thickness (Horizontal distance measured on the outer alveolar plate 2mm below A Point)

15±1 mm

Protrusive lips

Recessive lips

8.

Upper lip Strain (Lip thickness form vermilion border of upper lip to the labial surface of max central incisor)

13-14 mm

Protrusive lips

Recessive lips


9.

Lower lip to H- line (Distance between the most prominent part of lower lip to H- line)


0-1 mm

Protrusive

lower lip



Recessive

lower lip




10.

Inferior Sulcus Depth (Distance betweeninferior labial sulcus to Hline)


5 mm

Increased depth of lower lip

Decreased depth of lower lip



11.

Soft tissue chin thickness (Distance between soft to hard tissuepogonion (Pog’-Pog)


10-12 mm

Protrusive chin

Recessive chin

Wits Analysis







Angles

Mean Values

Increased

Decreased

1.

AO-BO (Apical base position)

(A point and


B point
difference)

Males-1 mm

Females-0 mm



Skeletal Class 2

Skeletal class 3




BY :

Meera Alrazooqi & Asma Maryam Shakil




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