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Orthodontics

Cephalometric Landmarks & Angles Simplified

A simple, structured overview of key ceph landmarks and angles for exams.

Quick Answers

What is the most important cephalometric landmark?

Nasion, because it serves as a stable anterior cranial base reference for many angular measurements.

What does SNA measure?

The anteroposterior position of the maxilla relative to the cranial base.

What does SNB measure?

The anteroposterior position of the mandible relative to the cranial base.

What does ANB indicate?

Skeletal relationship between maxilla and mandible (Class I, II, or III tendency).

1. Why cephalometrics matter in exams

Cephalometric interpretation shows your ability to link skeletal pattern, dental compensation, and growth direction. Examiners expect concise, structured reporting — not memorized numbers.

  • Identify key points
  • Measure important angles
  • Interpret skeletal class
  • Discuss vertical and dental components

2. Essential cephalometric landmarks (memorize these)

Primary Skeletal Landmarks

  • Sella (S): midpoint of sella turcica
  • Nasion (N): frontonasal suture
  • A-point: deepest midline point on maxilla
  • B-point: deepest midline point on mandible
  • Pogonion (Pg): most anterior point on chin
  • Menton (Me): lowest point on mandibular symphysis

3. Dental landmarks you must know

Key Dental References

  • U1: long axis of maxillary incisor
  • L1: long axis of mandibular incisor
  • U6 / L6: molar positions (when part of analysis)

4. Fundamental cephalometric angles (with normal values)

These angles are repeatedly tested in exams:

Must-Know Angles & Values

  • SNA: 82° (maxillary position)
  • SNB: 80° (mandibular position)
  • ANB: 2° (skeletal class)
  • FMA: 25° (vertical growth pattern)
  • U1-SN: 102° (upper incisor inclination)
  • L1-MP: 90° (lower incisor inclination)

5. How to interpret skeletal class quickly

Use this universally accepted scheme:

  • Class I: ANB ≈ 2°
  • Class II: ANB > 4°
  • Class III: ANB < 0°

Remember: ANB alone isn't perfect — always cross-check with Wits appraisal.

6. Vertical pattern evaluation

Vertical dysplasia is a common exam topic. Key indicators:

  • FMA high: hyperdivergent, long face tendency
  • FMA low: hypodivergent, short face tendency
  • SN-MP angle: reinforces the pattern

7. Incisor inclination interpretation

Incisor angle changes help compensate skeletal patterns:

  • U1-SN ↑: proclined incisors
  • L1-MP ↑: proclined lower incisors (common in Class III compensation)
  • L1-MP ↓: retroclined lower incisors (common in Class II div 2)

8. Example OSCE-style cephalometric summary

Model Ceph Interpretation

Skeletal: SNA 80°, SNB 78°, ANB 2° → Skeletal Class I.

Vertical: FMA 29° → mild hyperdivergent pattern.

Dental: U1-SN 104° (proclined), L1-MP 92° (slightly proclined).

Summary: Class I skeletal base with mild vertical excess and compensatory incisor proclination.

9. How DentAIstudy helps

DentAIstudy can instantly convert cephalometric numbers into:

  • OSCE-style summaries
  • Diagnosis + interpretation templates
  • Flashcards for key angles
  • One-page orthodontic notes

Try Study Builder →

References

  • Proffit WR, Fields HW. Contemporary Orthodontics. (Reference-aligned summary)
  • Jarabak JR. Cephalometric analysis fundamentals. Am J Orthod.
  • Steiner CC. “Cephalometrics for you and me.” Am J Orthod.
  • McNamara JA. Cephalometric evaluation essentials.
  • Jacobson A. “Wits appraisal revisited.” Am J Orthod.