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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 describes commonly taught, protocol-dependent projections for nasal bone radiography — lateral, Waters (parietoacanthial), PA/Caldwell, and superoinferior tangential. There is no universal four-view series: obtain only the projections in the imaging order and validated facility protocol, modified for the patient's condition.

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

When radiography is specifically requested after clinical assessment, possible questions include:

Indication	Key Radiographic Finding
Nasal bone fracture	Discontinuity of bony cortex, depression, or fragmentation
Nasal alignment	Displacement that may be visible on a requested projection; management remains primarily clinical
Radiopaque foreign body	Only if composition and location make radiography appropriate
Associated facial injury	Do not use a limited nasal series to exclude complex midface injury; CT is generally preferred when such injury is suspected

Imaging-appropriateness correction: Isolated nasal fracture is usually diagnosed clinically, and many specialty guidelines state that plain films are not required because they do not reliably change management. In the ACR facial-trauma pathway for suspected nasal injury after the primary survey, CT maxillofacial without IV contrast is rated “Usually Appropriate,” while paranasal-sinus radiography is only “May Be Appropriate.” Do not escalate to CT merely because a nasal radiograph is negative; use CT when the examination suggests associated facial, orbital, NOE, skull-base, or intracranial injury.

Routine Views Overview

The table compares projections that may appear in textbooks or local protocols. It is not a universal exam recipe. SID, detector, grid use, exposure, and the exact projection set must come from the department's validated protocol and technique chart.

Projection	View	Example SID	Key Centering	Exposure
Lateral	One or both sides per protocol	40" (100 cm)	About ½" inferior to nasion	Local chart
Parietoacanthial (Waters)	PA	40" (100 cm)	Exiting acanthion	Local chart
PA/Caldwell-type (if specified)	PA	40" (100 cm)	Protocol-specific	Local chart
Superoinferior tangential (axial)	Tangential	40" (100 cm)	CR parallel to GAL, centered at nasion	Local chart

Each projection provides different information. Do not infer that all four are required, or add views solely for “comparison”; projection choice should be justified and protocol-based.

View 1: Lateral Nasal Bones — One or Both Sides per Protocol

The lateral projection profiles the nasal bones and soft-tissue nose. Some protocols obtain right and left laterals; others use a different limited series or no radiographs for uncomplicated isolated injury. If bilateral laterals are ordered, place the named side adjacent to the detector and use a radiopaque R/L marker on each exposure. The projections are not universally “mandatory.”

Patient Positioning

• Position: Erect, seated, recumbent, or horizontal-beam modification according to patient condition and local protocol
• 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	Digital detector/detail receptor appropriate to the system; do not place two exposures on one detector unless the system and protocol permit it
Grid	None — tabletop technique
Exposure	Use the validated local technique chart and target exposure index; no single kVp range applies to every digital system
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

Trauma Modification

Do not use an operator's finger to hold or reposition the patient's chin in the primary beam. If cervical-spine injury has not been excluded, maintain spinal precautions and do not flex, extend, or rotate the head merely to reproduce a textbook position. Use detector and horizontal-beam modifications, assistance devices outside the field, or defer the projection after discussion with the radiologist/clinical team.

Evaluation Criteria

• Coverage — Nasal bones, anterior nasal spine, frontonasal suture, and soft tissue nose must be visible
• Rotation — Paired structures expected on a true lateral should be closely superimposed; assess the nasal-bone cortical profile without claiming that the two bones will appear “symmetric”
• 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 PA facial-bones projection that may be included by local nasal-bone protocol. It demonstrates the bony nasal septum and adjacent midface, but a normal Waters image does not exclude a clinically important facial fracture and does not assess a septal hematoma.

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
Exposure	Validated local technique chart and exposure-index target
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 can depict the bony septum and gross adjacent facial-bone abnormality. Do not describe it as a screening test that rules out ZMC, orbital, or NOE fractures; when examination findings suggest complex injury, CT maxillofacial without IV contrast is the more appropriate initial study in the ACR pathway.

View 3: PA/Caldwell-Type Projection (Only If Specified)

A PA axial/Caldwell-type projection appears in some teaching and local facial-bone protocols, but it is not a universal nasal-bone view. The precise CR angle and exit point are protocol-dependent; a common Caldwell facial-bones setup uses a 15° caudal CR exiting at the nasion.

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
Exposure	Validated local technique chart and exposure-index target
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, protocol-dependent projection may demonstrate medial-lateral displacement of the distal nasal bones. It is also called a tangential or axial nasal-bones view; it should not be added automatically.

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
Exposure	Validated local technique chart and exposure-index target
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 (one or both per protocol)	Side being identified closest to IR, true lateral	Perpendicular to IR	About ½" below nasion	Usually nongrid
Waters	Erect or prone, chin on IR, OML ~37°	Perpendicular to IR	Exiting acanthion	Bucky
PA/Caldwell-type (if specified)	Forehead/nose at IR, OML ⟂	Often 15° caudal	Often exiting nasion	Per local protocol
Superoinferior tangential (if specified)	Seated erect or prone, chin on IR, GAL ⟂	∥ to GAL	Centered at nasion	Usually nongrid

Protocol-Sensitive Review — Nasal Bone Positioning

Fact	Details
Projection count	Not universal; use the order and local protocol. If both laterals are required, identify each with the correct radiopaque marker.
Lateral centering	A commonly taught method is about 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/Caldwell-type	Protocol-dependent; a common facial-bones method is 15° caudal with CR exiting the nasion
Tangential CR	Parallel to the GAL (glabelloalveolar line)
IR and grid	Choose for the installed system and validated protocol; lateral/tangential are commonly nongrid, while a broader facial-bone projection may use a grid
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
Wrong or absent side marker	Side cannot be established reliably	Place the correct radiopaque R/L marker at exposure without obscuring anatomy
Lateral centering too high (at nasion)	Anterior nasal spine cut off	Center ½ inch below the nasion
Patient rotated or tilted on lateral	Paired landmarks that should coincide are separated	Check MSP ∥ IR and IPL ⟂ IR, if movement is safe
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

Clinical Assessment Comes First

For uncomplicated isolated nasal trauma, fracture diagnosis and the decision to reduce are generally clinical; plain films often do not alter care. Follow-up after swelling subsides is commonly used to assess deformity. Imaging may still be requested for a specific local indication, but the technologist should not present a nasal series as obligatory for every tender or bruised nose.

When to Consider CT Instead

CT maxillofacial without IV contrast is preferred when there is concern for complex NOE or other facial fracture, ocular/orbital injury, malocclusion, CSF leak, neurologic signs, high-energy mechanism, or other significant associated injury. CT is not routinely needed for an uncomplicated isolated nasal fracture simply to confirm the diagnosis.

Pregnancy, Pediatrics, Dose, and Shielding

• Pregnancy: Verify pregnancy status according to policy, but do not withhold a clinically justified head/facial examination. Because the uterus is outside a tightly collimated nasal field, fetal exposure is from scatter and is very low. Consult the radiologist/medical physicist for unusual circumstances rather than quoting a universal patient dose.
• Pediatrics: Isolated nasal fractures are usually diagnosed clinically; pediatric guidance states that X-rays are not required, and CT is reserved for suspected associated fracture or intracranial injury. If imaging is justified, use age/size-appropriate technique, tight collimation, immobilization that avoids repeats, and only the requested views.
• Shielding: Do not apply gonadal or fetal shielding routinely. AAPM's shielding statement describes minimal to nonexistent benefit and possible obscuration, repeat imaging, or interference with exposure control. That AAPM policy was sunset at the end of 2024, so follow current facility policy; its evidence-based rationale remains useful for explaining why collimation and optimized technique—not routine contact shielding—provide the meaningful dose reduction.
• Exposure: Fixed “digital” kVp ranges are not transferable among detectors. Use the validated technique chart and monitor the system's exposure index; do not increase exposure merely to make thin nasal bones look darker.

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 — Educational Practice Questions

Quick Reference — Nasal Bone Positioning Checklist

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

• ✅ Ordered projection set checked against the local protocol; no automatic extra views
• ✅ Correct radiopaque side marker placed for every projection
• ✅ Detector, SID, grid, and exposure selected from the validated local chart
• ✅ For the commonly taught lateral method, CR centered about ½ inch below the nasion
• ✅ IPL perpendicular to IR (no tilt) on lateral
• ✅ Waters view — OML at 37°, CR exiting the acanthion
• ✅ PA/Caldwell-type — use 15° caudal/exiting nasion only if specified by protocol
• ✅ Superoinferior tangential — CR parallel to GAL (if ordered)
• ✅ Collimation tight to the nasal region on all views
• ✅ No motion — sharp bony margins confirmed

Authoritative Sources

• ACR Appropriateness Criteria®: Imaging of Facial Trauma Following Primary Survey — Variant 3 addresses suspected nasal injury.
• Royal Children's Hospital Melbourne Clinical Practice Guideline: Nasal fracture — clinical diagnosis, imaging limits, and same-day septal-hematoma exclusion.
• Merck Manual Professional: Nasal Fractures — peer-reviewed specialty overview, clinical diagnosis, and immediate septal-hematoma drainage.
• CMAJ: Nasal fractures (peer-reviewed clinical review).
• AAPM Position Statement 32-A: Use of Patient Gonadal and Fetal Shielding — archived official statement (policy sunset December 31, 2024) documenting the rationale against routine shielding.
• IAEA Radiation Protection of Patients: Pregnant women.
• ARRT Examination Content Specifications — official exam scope; not a facility protocol.