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. 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 Downs (1948) 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.
• 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 compromises — 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.

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 ANB. 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 white Western sample. For patients of other ancestries, supplement with population-specific norms.

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.

Frequently Asked Questions