📊 Skeletal Classification
Skeletal Class (ANB)—
Maxillary Position (SNA)—
Mandibular Position (SNB)—
Growth Pattern (GoGn-SN)—
Facial Type (FMA)—
MMPA—
Björk Sum ∑ (N-S-Ar-Go-Me)—
Facial Convexity—
✨ Summary
Place S, N, A, B landmarks to see classification.
📝 Notes
✏️ Tracing Legend
H-Line (sPg–Ls, Holdaway)
Ba–N (Ricketts cranial base)
Occlusal Plane (3-pt when Op3 placed)
📍 Anatomical Landmarks
Click a landmark to select, then click on image. 0 of 30 placed.
💡 Tips
Place in order · Right-click (or long-press on tablet) to remove · Drag to reposition · Arrow keys to nudge (Shift = ×5) · ⊘ Skip = mark landmark intentionally absent (auto-advance will bypass it). Click the pip dot again to un-skip.
📐 Eastman Analysis
Eastman Dental Hospital (London) — UK standard orthodontic cephalometric analysis.
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 Eastman Norms
MMPA is the key vertical indicator. Upper incisors measured to maxillary plane (ANS–PNS), lower to mandibular plane (Go–Me).
📐 Steiner Analysis
Angular and linear measurements referenced to the SN plane.
| Measurement | Value | Norm | Dev / Needs |
|---|
📐 Downs Analysis
Skeletal and dental pattern evaluation (Downs 1948).
| Measurement | Value | Norm | Dev / Needs |
|---|
📐 Tweed Triangle
FMA + FMIA + IMPA = 180°. Mandibular incisor position assessment.
| Measurement | Value | Norm | Dev / Needs |
|---|
📐 McNamara Analysis
Linear measurements — requires calibration for mm values.
| Measurement | Value | Norm | Dev / Needs |
|---|
📐 Björk-Jarabak Analysis
Polygonal analysis using S, Ar, Go, Me. Requires Articulare (Ar) landmark.
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 Björk Sum of Angles
The sum of Saddle + Articular + Gonial (N-S-Ar + S-Ar-Go + Ar-Go-Me) predicts growth type. 396° ±6° is average. Above 402° = hyperdivergent (vertical) growth; below 390° = hypodivergent (horizontal) growth. Articulare (Ar) is the intersection of the posterior condyle outline with the cranial base.
📘 Face Height Ratio
Posterior face height (S–Go) divided by anterior face height (N–Me). Values above 65% indicate horizontal growth; below 59% suggests vertical growth tendency. Requires calibration for mm measurements.
📐 Ricketts Analysis
Ricketts cephalometric analysis — facial axis requires Basion (Ba) and Pterygoid (Pt).
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 Facial Axis
The angle between the cranial base (Ba–N) and the facial axis (Pt–Gn). At 90° the face is orthognathic. Opening (>90°) indicates dolichofacial tendency; closing (<90°) indicates brachyfacial. Requires Basion (Ba) and Pterygoid point (Pt).
📘 A-Po Line (Ricketts)
The A-pogonion line is Ricketts' dentoalveolar reference. Upper and lower incisors should be within 2–4 mm anterior to this line. Lower incisor position (1 mm ahead, 22° inclination) is the most diagnostically important measurement.
🫦 Holdaway Soft Tissue Analysis
Soft tissue evaluation referenced to the H-line (sPg–Ls). Requires Sn (subnasale) and Me' (soft tissue menton) — new landmarks in v2.
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 H-Line (Holdaway)
Runs from soft tissue Pogonion (sPg) to most prominent point of upper lip (Ls). The H-angle between H-line and NB line norms 7–10°. Increasing H-angle = lip protrusion relative to chin.
📘 New Landmarks Required (v2)
Sn — Subnasale: junction of nasal columella and upper lip in midsagittal plane.
Me' — Soft tissue Menton: most inferior point of soft tissue chin.
📏 Wits Appraisal
Sagittal jaw discrepancy measured on the functional occlusal plane — independent of SN plane. Requires Op1, Op2, A, B and calibration.
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 Wits Appraisal (Jacobson)
Perpendiculars are dropped from A and B points onto the functional occlusal plane. The distance between the two foot-points (AO–BO) reflects the sagittal jaw discrepancy without the distortion introduced by SN plane variations. Males: –1 mm ±2 mm; Females: 0 mm ±2 mm. Positive = AO ahead of BO (Class II tendency). Requires Op1 (posterior molar) and Op2 (anterior incisal contact) + calibration.
👄 E-Line Analysis
Soft tissue lip profile relative to the aesthetic plane — requires calibration for mm values.
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 E-Line (Ricketts)
Runs from Pronasale to soft tissue Pogonion. Negative = lip behind E-line (ideal). Requires Prn, Ls, Li, sPg soft tissue landmarks.
📐 Kim's Analysis
ODI + APDI skeletal pattern indicators and Extraction Index (Kim 1978).
| Measurement | Value | Norm | Dev / Needs |
|---|
📘 ODI — Overbite Depth Indicator
ODI = AB plane to mandibular plane angle + palatal plane to FH angle (signed). Quantifies the vertical skeletal relationship. ODI < 68.4° = open bite tendency; ODI > 80.6° = deep bite tendency.
📘 APDI — Anteroposterior Dysplasia Indicator
APDI = Facial angle + AB plane to N–Pg angle + palatal plane to FH angle (signed). Quantifies the sagittal skeletal pattern. APDI < 76.3° = Class II; APDI > 86.5° = Class III.
📘 EI — Extraction Index
EI = CF + (Interincisal Angle − 131.3°), where CF = ODI + APDI and 131.3° is Kim's interincisal norm. EI ≥ 161° → non-extraction; EI ≤ 155° → extraction indicated; 156–160° → borderline.