modified water facial bones

What is the Modified Waters Method?

Modified Parietoacanthial Projection of the Facial Bones. This is a special facial bone projection used primarily to evaluate the orbital floor.

What are the clinical indications for the Modified Waters projection?

Orbital fractures (especially blowout fractures), neoplastic or inflammatory processes, and foreign bodies in the eye. This view is commonly ordered when an orbital floor fracture is suspected.

Which type of fracture is best demonstrated with the Modified Waters projection?

Blowout fracture of the orbit. This is the classic projection for evaluating the orbital floor.

What is the minimum SID for the Modified Waters projection?

40 inches (100 cm). This is the standard SID for facial bone imaging.

What IR size is recommended?

8 × 10 inches (18 × 24 cm) or 10 × 12 inches (24 × 30 cm), portrait. These are standard facial bone image receptor sizes.

Is a grid recommended?

Yes. A grid improves image contrast.

What kVp range is recommended?

70–85 kVp. This range provides adequate penetration and detail.

What part of the face rests against the IR?

Chin and nose. This positioning is similar to the Waters projection.

Which line must be perpendicular to the IR in the Modified Waters projection?

LML (Lips-Meatal Line). This is the major difference from the regular Waters view.

What angle does the OML form with the IR in the Modified Waters projection?

55 degrees. In contrast, the regular Waters projection forms a 37° angle.

Which line is perpendicular to the IR in a regular Waters projection?

MML. This is used in the regular Waters projection.

Which line is perpendicular to the IR in a Modified Waters projection?

LML. This is specific to the Modified Waters projection.

How should the MSP be positioned?

Perpendicular to the IR. This prevents rotation and tilt.

What is the CR angle for a Modified Waters projection?

Perpendicular. No tube angle is used.

Where does the CR exit?

Acanthion. This is the same exit point as the regular Waters projection.

What landmark is associated with the Modified Waters projection?

Acanthion. Both Waters and Modified Waters exit at this landmark.

What anatomy is best demonstrated on a Modified Waters projection?

Inferior orbital margins (orbital floors). This is the main reason the projection is performed.

Why is the Modified Waters projection preferred for orbital floor evaluation?

It provides less distortion of the orbital floor.

What sinus is demonstrated on the Modified Waters projection?

Maxillary sinus. The maxillary sinuses remain visible.

What other structures are visualized?

Frontal sinuses, nasal septum, and orbital margins.

Where should the petrous ridges appear on a properly positioned Modified Waters projection?

In the lower half of the maxillary sinuses, below the IOMs. This confirms proper positioning.

Petrous ridges projected into the lower half of the maxillary sinuses indicate what?

Correct positioning and CR angulation.

How is rotation evaluated on a Modified Waters projection?

Equal distance from the midlateral orbital margin to the lateral cortex of the skull.

Which side appears wider if the patient is rotated?

The side rotated toward the IR.

What indicates no motion?

Sharp bony margins,

Waters vs Modified Waters

Modified Waters: LML ⟂ IR, OML 55°, exit at acanthion, less distortion of orbital floor. Waters: MML ⟂ IR, OML 37°, exit at acanthion, best for maxillary sinuses.

Memory Trick for Modified Waters projection

Modified Waters = More Neck Extension = Better Orbit View. Remember: LML ⟂ IR → OML 55° → Blowout Fractures → Orbital Floor.