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Nasal Bone X-Ray Positioning: Lateral, PA, Waters & Tangential Views

You're working a weekend ER shift when a patient comes in after a collision during a basketball game. There's swelling and tenderness over the bridge of the nose, and the ER physician wants nasal bone X-rays. As a radiologic technologist, your positioning needs to be spot-on — the nasal bones are small, thin, and easily obscured by even a slight rotation or poor centering.

This guide covers the four essential projections for nasal bone radiography — bilateral laterals, Waters (parietoacanthial), PA, and the superoinferior tangential view — with source-informed centering points, evaluation criteria, ARRT exam tips, and common positioning errors to avoid.

Clinical Anatomy of the Nasal Bones

The nasal bones are two small, oblong bones that sit side by side at the bridge of the nose, forming the nasal ridge. They articulate:

• Superiorly — with the frontal bone at the frontonasal suture
• Laterally — with the frontal processes of the maxillae
• Medially — with each other at the internasal suture
• Posteriorly — with the perpendicular plate of the ethmoid (forming part of the nasal septum)

The anterior nasal spine is a bony projection at the inferior margin of the nasal aperture. It's an important positioning landmark and must be included on the lateral projection.

Indications for Nasal Bone Radiography

A nasal bone X-ray series is typically ordered for:

Indication	Key Radiographic Finding
Nasal bone fracture	Discontinuity of bony cortex, depression, or fragmentation
Deviated nasal septum	Asymmetric nasal cavity on Waters view
Post-reduction evaluation	Alignment assessment after closed reduction
Suspected foreign body	Radiodense object on lateral projection
Facial trauma	Evaluate for associated midface fractures

Clinical pearl: While plain radiography remains the frontline study for isolated nasal trauma, CT is preferred for complex naso-orbito-ethmoid (NOE) fractures. If the clinical suspicion for a nasal fracture remains high after a negative X-ray, follow-up imaging or CT may be warranted.

Routine Views Overview

A complete nasal bone series traditionally includes three routine projections plus one supplemental view:

Projection	View	SID	Key Centering	kVp Range (Digital)
Lateral	Right & Left	40" (100 cm)	½" inferior to nasion	60–70
Parietoacanthial (Waters)	AP	40" (100 cm)	Exiting acanthion	75–85
PA (occipitofrontal 15° caudal)	PA	40" (100 cm)	Exiting nasion	70–80
Superoinferior tangential (axial)	Tangential	40" (100 cm)	Skimming nasion (∥ GAL)	60–70

Each projection provides specific diagnostic information, and the lateral view — obtained bilaterally — is the single most important projection.

View 1: Lateral Nasal Bones — Right and Left

The lateral projection is the primary view for evaluating the nasal bones. Bilateral laterals are required (right AND left) because each side is positioned closest to the IR, maximizing detail for side-to-side comparison. A single lateral or a PA projection alone is insufficient.

Patient Positioning

• Position: Erect or prone — erect is preferred for trauma patients to avoid head manipulation
• Side of interest: Closest to the IR (detail cassette or tabletop)
• Head position — True lateral:
  • Median sagittal plane (MSP) parallel to IR
  • Interpupillary line (IPL) perpendicular to IR
  • Infraorbitomeatal line (IOML) perpendicular to the front edge of the IR

Technical Factors

Parameter	Lateral Nasal Bones
SID	40" (100 cm)
IR	Detail cassette or non-screen film, 8 × 10 in, divided in half for bilateral views
Grid	None — tabletop technique
kVp	60–70 (digital); 50–60 (analog/screen-film)
CR	Perpendicular to IR
Centering point	½ inch (≈1.3 cm) inferior to the nasion — at the bridge of the nose
Collimation	Tightly to nasal region (≈4 × 5 in / 10 × 12 cm field)
Respiration	Suspended

Finger Technique

For the lateral view, a common challenge is superimposition of the mandibular ramus over the nasal bones. The finger technique addresses this: use a gloved finger to gently depress the chin slightly, extending the neck and moving the mandible out of the nasal bone field. This is a tabletop technique — no grid is used.

Evaluation Criteria

• Coverage — Nasal bones, anterior nasal spine, frontonasal suture, and soft tissue nose must be visible
• Rotation — Nasal bones should be symmetric; no rotation between sides
• Tilt — Orbital roofs superimposed (verifies IPL perpendicular to IR)
• Motion — Sharp bony margins and soft tissue borders
• Technique — Soft tissue density sufficient to outline nasal cartilage and soft tissue swelling if present

View 2: Parietoacanthial Projection (Waters Method)

The Waters view is a standard facial bones projection that is included in the nasal bone series because it demonstrates the bony nasal septum and identifies septal deviation or associated midface fractures.

Patient Positioning

• Position: Erect preferred (or prone with chin on IR)
• Chin resting on IR, neck extended
• Mentomeatal line (MML) perpendicular to the IR
• Orbitomeatal line (OML) forms approximately 37° with the IR
• MSP perpendicular to IR

Technical Factors

Parameter	Waters (Parietoacanthial)
SID	40" (100 cm)
IR size	8 × 10 in or 10 × 12 in
Grid	Bucky
kVp	75–85 (digital)
CR	Perpendicular to IR
Centering point	Exiting the acanthion — the junction of the nasal septum and upper lip
Respiration	Suspended

Evaluation Criteria

• Coverage — Maxillae, nasal septum, zygomas, orbital margins, anterior nasal spine
• Rotation — Equal orbital margins; nasal septum midline
• Petrous ridges — Should project just below the maxillary sinus floors
• Motion — Sharp margins of maxillae and sinuses

Clinical Application

The Waters view is particularly valuable for detecting deviated nasal septum, which may not be visible on the lateral projection. In nasal trauma cases, this view also screens for associated zygomaticomaxillary complex (ZMC) fractures — an important finding that can change the patient's management.

View 3: PA Nasal Bones (Occipitofrontal 15° Caudal)

The PA projection with 15° caudal angulation provides a straight-on frontal view of the nasal bones, projecting them below the superimposed frontal bone.

Patient Positioning

• Position: Prone, forehead and nose resting on the IR
• OML perpendicular to the plane of the IR
• MSP aligned to the midline of the IR and Bucky

Technical Factors

Parameter	PA Nasal Bones
SID	40" (100 cm)
IR size	8 × 10 in
Grid	Bucky
kVp	70–80 (digital)
CR angle	15° caudal
Centering point	Exiting the nasion — the depression at the root of the nose between the eyes
Respiration	Suspended

Evaluation Criteria

• Nasal bones and nasal aperture visible below the frontal bone
• Nasal septum aligned vertically (no rotation)
• Symmetry of bony nasal margins
• Sharp cortical outlines (no motion)

View 4: Superoinferior Tangential (Axial) View

This supplemental projection is invaluable for assessing medial-lateral displacement of nasal bone fractures — information that neither the lateral nor the PA view can fully provide. It's also called the "tangential nasal bones" or "axial nasal bones" view.

Patient Positioning

• Position: Seated erect (or prone with extended chin)
• Chin resting on IR
• Head extended so the glabelloalveolar line (GAL) is perpendicular to the IR
• MSP perpendicular to IR

The glabelloalveolar line (GAL) runs from the glabella (the smooth prominence on the frontal bone above the nose) to the alveolar ridge of the maxilla (anterior upper teeth). When correctly aligned perpendicular to the IR, the CR can skim across the nasal bridge without superimposition.

Technical Factors

Parameter	Superoinferior Tangential (Axial)
SID	40" (100 cm)
Grid	None — nongrid technique
kVp	60–70 (digital)
CR direction	Parallel to the glabelloalveolar line (GAL)
Centering point	Centered to the nasion, beam skims the glabella and anterior upper teeth
Respiration	Suspended

Evaluation Criteria

• Coverage — Mid- and distal nasal bones with soft tissue profile, minimal superimposition
• Rotation — Anterior nasal spine symmetric to outer soft tissue borders
• Extension — Correct GAL alignment: too much chin extension brings the alveolar ridge into view; too little leaves the glabella superimposed over the nasal bones
• Motion — Sharp nasal bone margins

Positioning Summary Table

View	Patient Position	CR Angle	Centering Point	Grid
Lateral (R & L)	Erect or prone, side of interest closest to IR, true lateral	Perpendicular to IR	½" below nasion	None (tabletop)
Waters	Erect or prone, chin on IR, OML ~37°	Perpendicular to IR	Exiting acanthion	Bucky
PA (15° caudal)	Prone, forehead on IR, OML ⟂	15° caudal	Exiting nasion	Bucky
Superoinferior tangential	Seated erect or prone, chin on IR, GAL ⟂	∥ to GAL	Skimming nasion	None

ARRT High-Yield Facts — Nasal Bone Positioning

Fact	Details
Bilateral laterals	Mandatory — right AND left, each with the side of interest closest to the IR
Lateral centering	½ inch (≈1.3 cm) below the nasion, CR perpendicular
Waters OML angle	37° to the IR plane; MML perpendicular
Waters centering	CR perpendicular, exiting the acanthion
PA CR angle	15° caudal, CR exits the nasion
Tangential CR	Parallel to the GAL (glabelloalveolar line)
IR size	8 × 10 in (detail for lateral, grid for PA/Waters)
Grid usage	Bucky for PA and Waters; nongrid for lateral and tangential
Key anatomy — lateral	Nasal bones, anterior nasal spine, frontonasal suture, soft tissue
Key anatomy — Waters	Bony nasal septum, maxillae, zygomas, anterior nasal spine
Key anatomy — tangential	Mid- and distal nasal bones without superimposition

Common Positioning Errors

Error	Result	Fix
Single lateral instead of bilateral	Insufficient side-by-side comparison	Always obtain right AND left laterals
Lateral centering too high (at nasion)	Anterior nasal spine cut off	Center ½ inch below the nasion
Patient rotated on lateral	Asymmetric nasal bones — one appears wider	Check IPL ⟂ IR
Waters MML not perpendicular	Petrous ridges obscure maxillary sinuses	Verify MML is 90° to IR
Tangential view wrong CR angle	Glabella or teeth superimposed on nasal bones	CR parallel to GAL; adjust chin extension
Head tilted on PA	Nasal septum not midline	Center MSP to IR, check equal orbits

Clinical Indications

When to Order Nasal Bone X-Rays

• Nasal trauma — Falls, sports injuries, assaults with nasal swelling, bruising, or deformity
• Suspected nasal bone fracture — Point tenderness, crepitus, palpable step-off
• Post-reduction evaluation — Check alignment after closed reduction
• Suspected foreign body — Nasal cavity radiodense foreign body in pediatric or adult patients

When to Consider CT Instead

CT of the facial bones is preferred when there is clinical concern for complex naso-orbito-ethmoid fractures, associated orbital wall fractures, or significant soft tissue injury that may involve the nasal septum or lacrimal apparatus. Plain radiography is appropriate for isolated, clinically suspected nasal bone fractures without concerning associated findings.

Internal Linking — Build Your Knowledge

This nasal bone positioning guide is part of a complete library of head and facial positioning resources. Deepen your understanding with these related articles:

• Facial Bones X-Ray Positioning — Waters, Caldwell, lateral, and SMV views for the complete facial skeleton
• Paranasal Sinuses X-Ray Positioning — Caldwell, Waters, lateral, and SMV sinus projections
• Skull X-Ray Positioning — Lateral, PA, AP, Towne, and Caldwell skull projections
• X-Ray Modality Overview — General radiography technique and physics
• Trauma Radiography Principles — Modified positioning for emergency and non-ambulatory patients

Test Your Knowledge — ARRT-Style Practice Questions

Quick Reference — Nasal Bone Positioning Checklist

Use this checklist before every nasal bone X-ray exam:

• ✅ Bilateral lateral views planned — right AND left
• ✅ Detail cassette or tabletop technique for laterals
• ✅ CR centered ½ inch below the nasion for laterals
• ✅ IPL perpendicular to IR (no tilt) on lateral
• ✅ Waters view — OML at 37°, CR exiting the acanthion
• ✅ PA view — 15° caudal, CR exiting the nasion
• ✅ Superoinferior tangential — CR parallel to GAL (if ordered)
• ✅ Collimation tight to the nasal region on all views
• ✅ No motion — sharp bony margins confirmed