Zygomatic Arch X-Ray Positioning: SMV, Tangential, Towne & Titterington Views
The zygomatic arch (cheekbone) is one of the most commonly fractured facial bones — second only to the nasal bones. It's formed by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone, joined by the zygomaticotemporal suture. When a patient comes in after a fistfight, sports injury, or MVA with facial swelling and tenderness over the cheek, you'll be asked to image the zygomatic arches.
As a radiologic technologist, you need to know four dedicated projections for the zygomatic arch series, plus their centering points, critical angles, and contraindications. These are frequently tested on the ARRT exam, and getting them right matters — a missed depressed fracture can lead to malunion, cosmetic deformity, and functional problems with mastication.
This guide covers all four views: SMV (bilateral), tangential jug handle (unilateral), AP axial modified Towne, and PA axial modified Titterington, with Clark's-sourced positioning data, centering point tables, evaluation criteria, and exam tips.
Anatomy of the Zygomatic Bone
Before we get into positioning, let's review the key anatomy. The zygomatic bone is a paired, quadrilateral-shaped bone that forms the prominence of your cheek (the "malar" prominence). Each bone has four processes that connect it to surrounding structures:
| Structure | Connection | Clinical Notes |
|---|---|---|
| Frontal process | Articulates with frontal bone (zygomaticofrontal suture) | Forms lateral orbital wall; Whitnall's tubercle attachment |
| Temporal process | Articulates with zygomatic process of temporal bone | Forms the zygomatic arch itself |
| Maxillary process | Articulates with maxilla (zygomaticomaxillary suture) | Forms inferolateral orbital rim |
| Sphenoid articulation | Greater wing of sphenoid | Deep orbital wall component |
The zygomatic arch provides width to the face and plays an important functional role in protecting the orbit and providing attachment for the masseter muscle. Fractures here can affect chewing.
Zygomatic Fracture Patterns
You'll encounter three main fracture patterns:
- Simple (isolated) arch fracture — A single break in the arch, usually from a direct blow (e.g., a clenched fist). The depressed fragment may impinge on the coronoid process of the mandible, limiting mouth opening.
- Tripod fracture (zygomaticomaxillary complex) — Three fracture lines through the zygomaticofrontal suture, zygomaticomaxillary suture, and zygomatic arch. The zygomatic bone becomes a free-floating fragment. This is the most common pattern from high-impact trauma like MVAs.
- Le Fort III fracture — A transverse craniofacial dissociation that involves the pterygoid plates, nasal bones, and zygomatic arches. The entire midface is detached from the skull base.
💡 ARRT Exam Tip
The ARRT frequently tests fracture pattern recognition. Remember: Tripod = three sutures (frontozygomatic + zygomaticomaxillary + arch). Le Fort III = complete midface separation involving pterygoid plates. The Waters view is the single best projection for evaluating Le Fort fractures because it shows the maxillary sinuses, orbital floors, and zygomatic arches in one image.
Routine Projections for the Zygomatic Arch Series
The zygomatic arch series traditionally includes four projections:
- SMV (Submentovertex) — Bilateral, both arches in one image
- Oblique Inferosuperior Tangential (Jug Handle) — Unilateral, side of injury
- AP Axial Modified Towne — Bilateral overview
- PA Axial Modified Titterington — Bilateral, alternative to Towne
In clinical practice, the SMV and Tangential (jug handle) views are the most commonly performed. The Towne and Titterington views are often part of a comprehensive facial bone series or used when the SMV is contraindicated.
View 1: Submentovertex (SMV) — Bilateral Zygomatic Arches
The SMV provides a bird's-eye view of the skull base and is the best single projection for evaluating both zygomatic arches simultaneously.
Patient Positioning
- Position: Upright (seated) or supine with shoulders elevated on firm pillows
- Neck: Fully extended so the vertex of the skull rests on the IR
- MSP: Perpendicular to the IR (centered to midline)
- IOML: As parallel as possible to the IR plane
⚠️ Clinical Pearl
The SMV requires significant neck hyperextension. NEVER attempt this projection on a patient with a suspected cervical spine injury — you could displace an unstable vertebral fracture. Use the tangential jug handle view as an alternative. Also, do not leave the patient in this position longer than necessary — the increased cranial pressure can leave them dizzy once they sit up.
Technical Factors
| Parameter | SMV Zygomatic Arches |
|---|---|
| Projection | Submentovertex (inferosuperior) |
| SID | 100 cm (40 in) |
| IR size | 24 × 30 cm (10 × 12 in), crosswise or lengthwise |
| CR | Perpendicular to IOML |
| Centering point | Midway between the angles of the mandible (approximately 1 inch/2.5 cm posterior to outer canthus) |
| Grid | Yes |
| Respiration | Suspended |
| AEC | Not recommended |
Evaluation Criteria
- Both zygomatic arches should be visible free of superimposition
- No foreshortening or rotation of the arches
- IOML should appear as a sharp line without double contours
- Symmetric visualization — rotation would show asymmetric arch projection
View 2: Oblique Inferosuperior Tangential (Jug Handle View) — Unilateral
This is the dedicated unilateral view for the injured zygomatic arch. It's also called the "jug handle view" because the arch looks like a bucket handle on the image.
Patient Positioning
- Position: Upright (seated) or supine with neck gently hyperextended
- Head: Top of head on the IR
- IOML: As parallel as possible to the IR
- Rotation: Rotate the head 15° from the midline toward the side of injury
- Tilt: Tilt the chin 15° toward the zygomatic arch being imaged
Technical Factors
| Parameter | Oblique Inferosuperior Tangential |
|---|---|
| Projection | Inferosuperior tangential |
| SID | 100 cm (40 in) |
| IR size | 18 × 24 cm (8 × 10 in) — "cone-down" view |
| CR | Perpendicular to IOML |
| Centering point | Centered directly to the zygomatic arch of interest |
| Grid | Yes |
| Respiration | Suspended |
| AEC | Do NOT use AEC — use manual technique |
💡 Clinical Pearl — AEC Pitfall
The tangential (jug handle) view is a coned-down projection of a thin bony structure surrounded by air and soft tissue. AEC will overexpose the image because the ionization chambers detect insufficient attenuation through the arch. Use a manual technique with slightly less than the normal zygomatic arch exposure factors — typically around 60–65 kVp with a low mAS.
Evaluation Criteria
- Zygomatic arch of interest should be free from superimposition by other bony structures
- The arch should appear as an isolated, well-defined bony curve
- Adequate exposure (not over- or underexposed)
- The CR skims the mandibular ramus to project the arch clear of the mandible
View 3: AP Axial Modified Towne Method — Bilateral
The modified Towne view is an excellent alternative when the SMV cannot be performed. It provides a bilateral view of the zygomatic arches projected lateral to the mandibular rami.
Patient Positioning
- Position: Upright (seated) or supine
- Head: OML perpendicular to the IR; MSP perpendicular to the IR
- Neck: Flexed as needed to achieve OML perpendicular
Technical Factors
| Parameter | AP Axial Modified Towne |
|---|---|
| Projection | AP axial |
| SID | 100 cm (40 in) |
| IR size | 24 × 30 cm (10 × 12 in), lengthwise or crosswise |
| CR | 30° caudal to OML |
| Centering point | Glabella (entering) |
| Grid | Yes |
| Respiration | Suspended |
If the Patient Cannot Flex the Neck
If the patient cannot flex their neck sufficiently to position the OML perpendicular (common in elderly patients or those with cervical arthritis), adjust the positioning:
- Position the IOML perpendicular to the IR
- Increase the caudal angle to 37°
- Keep the MSP perpendicular to avoid rotation
Evaluation Criteria
- Zygomatic arches should be symmetrical and projected lateral to the mandibular rami
- Petrous pyramids should project below or through the maxillary sinuses (angle-dependent)
- No rotation — the arches should be equidistant from the skull midline
View 4: PA Axial Modified Titterington Method — Bilateral
The Titterington method is a PA approach that produces similar results to the Towne view. Some protocols use it as the standard bilateral zygomatic arch projection.
Patient Positioning
- Position: Upright (seated) or prone
- Head: Chin and tip of nose rest gently on the IR
- MSP: Perpendicular to the IR (centered to midline)
Technical Factors
| Parameter | PA Axial Modified Titterington |
|---|---|
| Projection | PA axial |
| SID | 100 cm (40 in) |
| IR size | 24 × 30 cm (10 × 12 in) |
| CR | 23°–38° caudal |
| Centering point | Midway between the zygomatic arches (exits at the vertex) |
| Grid | Yes |
| Respiration | Suspended |
Angle Selection
The CR angle for the Titterington method has a range of 23° to 38° caudal depending on the anatomy being prioritized:
- 23°–25° — Best for visualizing the zygomatic arches through the facial bones
- 30° — Standard angle; shows arches projected clear of the petrous ridges
- 35°–38° — Useful for evaluating the internal auditory canals and petrous pyramids in addition to the arches
If the patient cannot assume the PA position (e.g., facial trauma, respiratory distress), substitute with the AP axial modified Towne method instead.
Evaluation Criteria
- Zygomatic arches should be symmetrical
- No rotation of the skull
- Arches visible without superimposition by the petrous ridges at the correct angle
- Adequate penetration through the skull base
Positioning Summary Table
| View | Patient Position | CR Angle | Centering Point | Best Use Case |
|---|---|---|---|---|
| SMV | Supine/seated, neck hyperextended, vertex on IR | Perpendicular to IOML | Midway between mandibular angles | Standard bilateral screening |
| Tangential (Jug Handle) | Head rotated 15°, chin tilted 15° | Perpendicular to IOML | Over zygomatic arch of interest | Depressed fracture, C-spine contraindication |
| AP Axial Towne | Supine/seated, neck flexed | 30° caudal (OML) / 37° (IOML) | Glabella | Alternative to SMV; trauma patients |
| PA Axial Titterington | Prone/seated, chin + nose on IR | 23°–38° caudal | Midway between zygomatic arches | Standard PA approach; also shows IACs |
ARRT High-Yield Facts
| Fact | Details |
|---|---|
| Most common facial fracture | Nasal bones (1st), zygomatic bones (2nd), mandible (3rd) |
| SMV contraindication | Suspected cervical spine injury — neck hyperextension is dangerous |
| SMV alternative | Reverse Waters view or tangential zygomatic arch projection |
| SMV centering point | Midway between angles of mandible, CR perpendicular to IOML |
| Tangential head rotation | 15° toward affected side |
| Tangential chin tilt | 15° toward zygomatic arch being imaged |
| Modified Towne angle | 30° caudal (OML) or 37° caudal (IOML) |
| Titterington angle range | 23°–38° caudal |
| AEC limitation | Do NOT use AEC for tangential jug handle view |
| Tripod fracture | Three fracture lines: frontozygomatic + zygomaticomaxillary + arch |
| Best view for Le Fort classification | Waters view (parietoacanthial projection) |
| Common SMV error | Rotation causing asymmetric arch visualization |
Common Positioning Errors
Rotation on SMV
Rotation is the most common error. When the MSP isn't perpendicular to the IR, one zygomatic arch appears elongated and the other foreshortened. Check your MSP alignment before exposing — palpate the nasion and external occipital protuberance to confirm.
Insufficient Neck Extension on SMV
If the IOML is not parallel to the IR, the arches will appear foreshortened and superimposed by the mandible. The patient needs to extend their neck fully so the vertex touches the IR. Use pillows under the shoulders for supine patients to achieve full extension.
Wrong CR Angle on Towne or Titterington
Use too steep an angle and the arches project too far inferiorly, superimposing on the mandible. Use too shallow an angle and the petrous ridges obscure the arches. Double-check your angle before exposing.
Underexposure on Tangential View
Because the zygomatic arch is a thin bony structure, it's easy to underexpose when using standard technique. AEC makes this worse — it overexposes because it reads the arch as not enough attenuation. Use manual technique with 60–65 kVp and a low mAS.
💡 ARRT Exam Tip
The ARRT registry loves to test the SMV contraindication in trauma scenarios. You'll get a question like: "A patient arrives with facial swelling after an MVA. Cervical spine injury has not been ruled out. Which zygomatic arch projection should be performed?" The answer: Tangential (jug handle) view — it requires minimal neck movement. The follow-up might ask about centering: CR perpendicular to IOML, centered over the zygomatic arch of interest.
Clinical Indications
When to Order a Zygomatic Arch Series
- Facial trauma — Assault, MVA, sports injury with cheek swelling
- Suspected zygomatic fracture — Pain, tenderness, deformity over the cheekbone
- Trismus (limited mouth opening) — May indicate a depressed arch impinging on the coronoid process
- Periorbital ecchymosis — "Black eye" with subconjunctival hemorrhage may indicate orbital floor involvement
- Step deformity — Palpable irregularity along the infraorbital rim or zygomatic arch
When to Skip Plain Films and Go to CT
In many modern trauma centers, CT has replaced plain film radiography for complex facial fractures. However, plain films remain valuable in smaller hospitals without 24/7 CT access, follow-up evaluation of known fractures, initial screening for isolated zygomatic trauma, and patients with contraindications to CT. If there's clinical suspicion for a tripod fracture or Le Fort pattern, a facial bone CT with 3D reconstruction is the gold standard.
Related Articles
- Facial Bones X-Ray Positioning Guide — Waters, Caldwell, lateral, and SMV facial bone views with centering points
- Skull X-Ray Positioning Guide — Lateral, PA, Caldwell, Towne, and AP views for cranial radiography
- Mandible X-Ray Positioning Guide — PA, AP axial Towne, axiolateral oblique, and SMV mandibular views
- Trauma Radiography Principles — Modified techniques for non-ambulatory and facial trauma patients
- X-Ray Modality Page — Complete list of radiographic procedures and positioning guides