Steiner Analysis: A Complete Cephalometric Guide

History and Origins of the Steiner Analysis

The Steiner analysis was introduced by Cecil C. Steiner in a landmark 1953 paper in the American Journal of Orthodontics,¹ and expanded in a second paper in The Angle Orthodontist in 1959.² Steiner's goal was practical: create a cephalometric framework that a clinician could apply chairside, using a small number of meaningful measurements to characterise facial morphology and guide treatment planning. His analysis built on the earlier work of Downs³ but replaced the Frankfort Horizontal with the Sella-Nasion (SN) plane as the primary reference — a choice that proved highly reproducible and clinically durable.

More than seven decades later, Steiner analysis remains the most universally taught cephalometric analysis in orthodontic education globally. Its SNA, SNB, and ANB measurements are part of the clinical vocabulary of every orthodontist, and ANB in particular has become the shorthand for sagittal jaw classification in both clinical practice and research.

The SN Plane: Why It Works as a Reference

The SN plane connects Sella (S) — the geometric centre of the pituitary fossa — to Nasion (N), the most anterior point of the frontonasal suture. This line approximates the anterior cranial base and has two properties that make it a reliable cephalometric reference:

• Reproducibility: Both S and N are clearly identifiable on a lateral cephalogram with low inter-operator variability — among the most reliably located of all cephalometric landmarks.⁴
• Growth stability: The anterior cranial base completes most of its growth early in development, making SN a relatively stable reference across serial records in adolescent patients.

All angular measurements in the Steiner analysis are expressed as deviations from — or in relation to — this SN baseline, giving the analysis an internal geometric consistency that makes clinical comparisons straightforward.

Skeletal Measurements: SNA, SNB, and ANB

The three skeletal measurements of the Steiner analysis define the sagittal positions of the maxilla and mandible relative to the cranial base, and their relationship to each other.

Interpreting the ANB Angle

ANB is the most clinically consequential measurement in the Steiner analysis. It represents the sagittal discrepancy between the maxillary and mandibular apical bases and directly informs the skeletal classification of the malocclusion:

Dental Measurements

Beyond skeletal classification, the Steiner analysis characterises the position and angulation of the upper and lower incisors — critical for treatment planning, extraction decisions, and incisor torque prescriptions.

How Steiner Analysis Guides Treatment Planning

Skeletal vs. Dental Aetiology

The most important treatment planning decision the Steiner analysis informs is whether a malocclusion is skeletal (jaw position discrepancy) or dental (tooth position on a normal skeletal base). A Class II molar relationship with a normal ANB of 2° suggests dental Class II — amenable to mechanics alone. The same molar relationship with ANB of 7° indicates a skeletal Class II requiring growth modification in a growing patient or orthognathic surgical consideration in an adult.

Incisor Position and the Extraction Decision

Steiner's incisor measurements directly feed the extraction versus non-extraction decision. Proclined lower incisors (L1–NB above 27°) in a crowded arch suggest that extraction space may allow beneficial retroclination. Conversely, retroclined incisors (L1–NB below 23°) in a borderline case argue against extraction — further retroclination risks compromising the lip profile and airway volume. The interincisal angle provides an additional check: post-treatment, the target is typically 131° ± 6° with coordinated U1 and L1 positions.

Steiner's Compromise Concept

Steiner himself introduced the concept of acceptable compromises² — recognising that a patient presenting with ANB of 6° cannot always be treated to an ANB of 2°. He developed tables of acceptable incisor positions corresponding to each ANB value, allowing the clinician to plan a realistic tooth position outcome given a non-ideal skeletal base. BCeph's Steiner report displays both the normative value and the patient's actual deviation, giving the clinician the data needed to apply this reasoning directly.

How Reliable Are the Numbers? Landmark Error and Reproducibility

Every value in a Steiner analysis is derived from the position of a handful of points on the film. The measurements are only ever as good as the landmarks behind them, and the dominant source of error is not arithmetic — it is landmark identification.⁴

In their classic reliability studies, Baumrind and Frantz showed that each cephalometric landmark carries its own characteristic envelope of error.⁴ Some points are highly reproducible: Sella and Nasion, the two anchors of the SN plane, are located with low inter-operator variability. Others scatter far more — condylion, gonion, the incisor apices, and soft-tissue points are placed less consistently, and dental landmarks in particular show comparatively low reliability. The scatter also tends to be directional, each landmark spreading along a predictable axis rather than in a uniform circle.

Digital tracing versus hand tracing

Moving from acetate and protractor to on-screen digital tracing removes two whole categories of error: misreading a ruler or protractor, and mistakes in the manual calculation of derived values. Image enhancement — adjusting contrast, inverting, magnifying — can also make certain landmarks easier to locate. A 2024 systematic review and meta-analysis found digital cephalometric tracing to be as reliable as conventional hand tracing across skeletal and dental measurements.⁸ What software cannot remove is the irreducible core: deciding exactly where each landmark sits. That judgement stays operator-dependent on any platform.

The practical implications are straightforward. Calibrate your landmark placement, and re-check the points that are known to be unreliable. Treat sub-degree and sub-millimetre differences with caution rather than reading clinical meaning into them. Where possible, have the same operator trace serial records so that identification error stays consistent across time points. Running the analysis in BCeph eliminates the arithmetic entirely — every angle is computed from a single set of landmarks — so the only variable left in your hands is where those landmarks go.

Do Steiner's Norms Fit Your Patient?

Steiner derived his reference values from a specific and fairly small sample of individuals of European ancestry with good occlusion.¹ He presented them as clinically useful reference points, not as universal biological constants — a distinction that is easy to lose once a figure like "SNA 82°" has been repeated in enough textbooks.

Cephalometric norms vary systematically between populations, and a large body of work has re-derived Steiner values for different groups. A 2022 systematic review of norms for the north Indian population documented meaningful departures from the original figures,⁹ and the classic standards established for Japanese populations likewise differ across several skeletal and dental measurements.¹⁰ Patterns such as greater bimaxillary dental protrusion, or different incisor inclinations, recur across a number of non-European samples.

The clinical consequence is real: applying a single norm set to every patient risks over-diagnosing skeletal or dental discrepancy in someone whose population baseline simply sits elsewhere. Where validated population-specific norms exist, use them. Where they do not, read each deviation alongside the patient's ancestry, soft-tissue profile, and overall presentation. And remember that norms are ranges, not thresholds — a value one standard deviation from the mean is common, and not in itself a diagnosis. The numbers inform clinical judgement; they do not replace it.

Limitations and When to Supplement Steiner Analysis

Despite its clinical ubiquity, Steiner analysis has recognised limitations that practitioners should account for:

• SN plane variation. Individual differences in SN inclination introduce systematic bias into SNA, SNB, and ANB⁷ (see reliability). In patients with steep or flat cranial bases, Frankfort-referenced analyses (Ricketts, Downs) should be used to cross-check skeletal findings.
• No vertical component. Steiner analysis does not directly assess vertical skeletal relationships — the mandibular plane angle, lower facial height proportion, or hypodivergent/hyperdivergent pattern. Supplement with Björk-Jarabak or the FMA from the Tweed triangle for vertical diagnosis.
• No soft-tissue measurements. Beyond the Pg–NB value, Steiner provides no direct soft-tissue assessment. The Holdaway analysis, E-Line (Ricketts), or H-Line provide the lip and profile measurements needed for complete treatment planning.
• Population norm origin. Steiner's original normative values were derived from a small sample of European ancestry.¹ For patients of other ancestries, use validated population-specific norms where they exist (see population variation).⁹

BCeph addresses all four of these limitations by running Steiner alongside Ricketts, Björk-Jarabak, Holdaway, and eight other analysis modules from a single set of landmarks — so the full clinical picture is available in one session.

References

1. Steiner CC. Cephalometrics for you and me. Am J Orthod. 1953;39(10):729–755. doi:10.1016/0002-9416(53)90082-7
2. Steiner CC. Cephalometrics in clinical practice. Angle Orthod. 1959;29(1):8–29. Full text
3. Downs WB. Variations in facial relationships: their significance in treatment and prognosis. Am J Orthod. 1948;34(10):812–840. PubMed
4. Baumrind S, Frantz RC. The reliability of head film measurements. 1. Landmark identification. Am J Orthod. 1971;60(2):111–127. doi:10.1016/0002-9416(71)90028-5
5. Jacobson A. The “Wits” appraisal of jaw disharmony. Am J Orthod. 1975;67(2):125–138. doi:10.1016/0002-9416(75)90065-2
6. Hussels W, Nanda RS. Analysis of factors affecting angle ANB. Am J Orthod. 1984;85(5):411–423. PubMed
7. Järvinen S. An analysis of the variation of the ANB angle: a statistical appraisal. Am J Orthod. 1985. doi:10.1016/0002-9416(85)90024-7
8. Narkhede S, Rao P, Sawant V, et al. Digital versus manual tracing in cephalometric analysis: a systematic review and meta-analysis. J Pers Med. 2024;14(6):566. PubMed
9. Girhe V, Borle R, Datey P, et al. Cephalometric norms for the north Indian population: a systematic review. Natl J Maxillofac Surg. 2022;13(2):172–179. doi:10.4103/njms.NJMS_34_20
10. Miura F, Inoue N, Suzuki K. Cephalometric standards for Japanese according to the Steiner analysis. Am J Orthod. 1965;51(4):288–295.

Links open the journal record, PubMed entry, or DOI resolver. Normative values throughout this guide are documented reference ranges, not universal constants — see the section on population variation above.

Frequently Asked Questions