Friday, March 7, 2014



Pathology Demonstrated:

  • Orbital fissures like blow out and neoplastic / inflammatory processes are shown. Foreign bodies in the eye also may be demonstrated in this position.

Technical Factors:

  • IR size 18 x 24 cm (8 x 10 inches), lengthwise
  • Moving or stationary grid
  • 70 to 80 kV range
  • Small focal spot
  • mAs 18

Patient Position:

modified waters facial bone
Modified Waters  OML 55 degrees
  • Remove all metallic or plastic objects from the head and neck. Patient position is erect or prone but erect is preferred is patient's condition allows.

Part Position:

  • Extend neck chin and nose against table or bucky surface.
  • Adjust head until Lips Meatal Line (LML) is perpendicular; Orbitomeatal Line (OML) forms a 55 degree angle with the IR.
  • Position Mid Sagital Plane (MSP) perpendicular to the middle of the grid or the table or upright bucky surface. Ensure no rotation ot tilt of hand.

Central Ray:

  • Align Central Ray perpendicular, centered to exit at acanthion.
  • Center Image receptor to Central ray


  • Collimate to within 1 inch or 2.5 cm of facial bones.

Respiration of patient:

  • Suspend respiration during exposure.

Radiographic Criteria:

Structure shown:

facial bone x ray
Modified Parietoacanthial (Waters)
  • Orbital floor (plates) are visible with this projection, which also provides a less distorted view of the entire orbital rims than a parietoacanthial  (Waters Method) projection.


  • Correct position / CR angulation is indicated by petrous ridges projected into the lower half on the maxillary sinuses, below the inferior orbital rim.
  • No rotation of the cranium is indicated by equal distance from the midlateral orbital margin to the outer skull margin on each side.

Collimation and Central Ray:

  • The inferior orbital rim should be located at the center of the image.
  • The entire orbital rim and maxillary bones should be included in the collimated field.

Exposure Criteria:

  • Contrast and density are sufficient to visualize the orbital floors.
  • Sharp bony margins indicated no motion.

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