The Inferosuperior Projection of the Zygomatic Arches X-Ray (commonly referred to as the “Jug-Handle” View or Tangential Zygomatic Arch Projection) is a specialized, low-exposure axial view designed to project the delicate, slender zygomatic arches free of overlying facial and cranial bone superimposition.
It includes two primary modalities:
Detailed Indications:
Contraindications & Limitations:
Because the zygomatic arches are thin, superficial bony bridges surrounded by soft tissue and air, using standard skull/base exposure will completely burn them out. Exposure factors must be substantially reduced compared to a standard skull SMV.
| Parameter | Bilateral SMV Arch Technique | Unilateral Tangential Technique | Radiographic Rationale |
| Patient Posture | Erect (Seated) or Supine | Erect (Seated) or Supine | Erect allows maximal neck extension |
| Image Receptor (IR) | 24 x 30 cm (Landscape/Crosswise) | 18 × 24 cm (Portrait) | Captures bilateral spread vs. isolated arch |
| SID | 100 to 115 cm ( 40 to 44 inches) | 100 to 115 cm ( 40 to 44 inches) | Maintains geometric resolution |
| Grid Usage | Grid (focused 8: 1) or Non-Grid | Grid (focused 8: 1) or Non-Grid | Clean scatter; tabletop used for thin patients |
| Tube Potential (kVp) | 65 – 70 kVp (Low) | 60 – 68 kVp (VeryLow) | High-contrast resolution; avoids over-penetration |
| mAs Range | 8 – 15 mAs (≈ 50%of Skull Base) | 6- 10 mAs(Reduced) | Low exposure prevents burning out thin cortical rims |
| Focal Spot | Small (0.6 mm) | Small (0.6 mm) | Critical for resolving non-displaced hairline fractures |
| Breathing | Suspended respiration | Suspended respiration | Eliminates respiratory and swallowing motion |
Neck is hyper-extended until the infraorbitomeatal line is parallel to the plane of the image receptor.
Direct the perpendicular beam midway between zygomatic arches, entering 1 inch below the mandibular symphysis.
Mid-sagittal plane is centered perpendicular to prevent asymmetric overlap of arches on cranial anatomy.
Use lower mAs/kVp technique compared to routine cranial SMV to prevent burnout of thin zygomatic arches.
When an arch is flat or depressed into the temporal fossa, a standard SMV will superimpose the parietal bone over the arch. The tangential technique isolates that single arch:
3-Step Tangential Positioning Rule (Unilateral Zygomatic Arch)
| Error Type | Radiographic Sign on Film | Clinical Impact | Correction |
| Under-Extension (Neck not extended enough) | Mandibular symphysis/body superimposes over and obscures the anterior zygomatic arches. | Obscures anterior arch fractures and ZMC joints. | Extend neck further until IOML is strictly parallel to IR. |
| Over-Penetration (Standard skull kVp/mAs used) | The zygomatic arches are completely burned out (radiolucent void). | Fails to detect cortical integrity or fractures. | Reduce mAs by 50% and lower kVp to 65-70 kVp. |
| Head Rotation (in Bilateral view) | One zygomatic arch is projected wide; the other is superimposed over the lateral skull wall. | Creates false asymmetry mimicking arch depression. | Realign the Mid-Sagittal Plane (MSP) perpendicular to the IR. |
| Incorrect Angle in Tangential View | Parietal bone or mandibular ramus overlaps the isolated arch. | Total failure of tangential projection. | Strictly maintain the 15⁰ rotate toward / 15⁰ tilt away rule. |
Both zygomatic arches are projected laterally without superimposition on the parietal bones or mandible.
Chin and symphysis are hyper-extended anteriorly, preventing overlap across the temporal and zygomatic bones.
Symmetric distance from arches to lateral cranial cortex confirms precise MSP perpendicularity.
Low-contrast technical factors prevent burnout of the delicate zygomatic temporal processes.