AP axial (Towne Method): Skull series

SKULL SERIES

AP AXIAL PROJECTION:(TOWNE METHOD)
SKULL SERIES
Pathology Demonstrated

skull fractures (medial and lateral displacement), NEOPLASTIC PROCESSES, AND PAGET'S disease are demonstrated

AP AXIAL PROJ.: (TOWNE METHOD)
SKULL SERIES
Technical Factors

IR size 10 x 12" (24 x 30 cm); length wise; moving or stationary grid; 70 to 80 kV; 20 mAs; small focal spot

AP axial projection: (TOWNE METHOD)
skull series
patient position and patient part

patient is erect or supine; depressed chin,
OML perpendicular to IR; (for patients unable to flex their neck, align IOML perpendicular to IR); align MSP to CR and midline of the grid or the table; check for no head rotation and no tilt

AP AXIAL PROJECTION:(TOWNE METHOD)
SKULL SERIES
central ray

angle CR 30° caudad to OML, or 37° caudad to IOML; center at the MSP 2 1/2 inches (6.5 cm) above the glabella to pass through the foramen magnum at the level of the base of the occipital bone;

What is the minimum SID for a AP axial projection (Towne Method) skull series?

40" (100 cm)

Collimate to what part of the body for an AP axial projections skull series (Towne Method)?

collimate to the outer margins of the skull

AP AXIAL PROJECTION:(TOWNE METHOD)
SKULL SERIES
respiration

suspend upon exposure

AP AXIAL PROJECTION:(TOWNE METHOD)
SKULL SERIES
structures shown

occipital bone, petrous pyramids, and foramen magnum, the dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum

________ of the CR will project the dorsum sellae above the foramen magnum and __________ will project the anterior arch of C1 into the foramen Magnum rather than the dorsum sellae

under angulation/ over angulation

Shifting of the anterior or posterior clinoids within the foramen indicate what?

tilt

When collimating, the entire skull is visualized. The ________ is near the top and the ___________ ___________ is in the approximate center

vertex
foramen magnum

AP AXIAL PROJECTION:(TOWNE METHOD)
SKULL SERIES
exposure criteria

density and contrast are sufficient to visualize occipital bone and sellar structures within the foramen magnum; sharp bony margins indicate no motion

AP axial (Towne Method): Skull series

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