Part 1 skull and facial bones

AP Axial (Towne Method)

˜CR 30° caudad to OML

ØOML perpendicular to IR

˜CR 37° to IOML

ØIOML perpendicular to IR

˜CR 2½ inches above glabella

AP Axial Trauma (Towne Method)

˜CR 30° caudad to OML

(Beam angle will be greater than 30)

˜CR 37° to IOML

(beam angle will be greater than 37)

˜CR 2½ inches above glabella

TRAUMA-

ANGLE BEAM TO GET

CR 30˚ CAUDAD TO OML

CR 37˚ TO IOML

Beam angle will be larger to get correct angle

Evaluation Criteria: AP Axial Towne & AP Axial Trauma Towne

˜Dorsum sellae & posterior clinoid processes projected within foramen magnum

˜Occipital bone, petrous pyramids, demonstrated

˜Entire skull visualized

˜No rotation or tilt

˜Petrous ridges symmetric

ØPetrous ridge will appear narrowed in the direction of rotation

Optimal exposure factors

Lateral Skull (SOI closest to IR)

˜TRUE lateral

˜MSP parallel to IR

˜Interpupillary perpendicular  IPL

˜IOML perpendicular front edge IR

˜CR 2 inches (5 cm) superior to EAM

Evaluation Criteria: Lateral Skull

˜Entire skull visualized

˜Sella Turcica and clivus in profile

˜Superimposed parietal bones

˜Superimposed mandibular rami

˜Superimposed anterior and posterior clinoid processes

˜Cranium seen without rotation or tilt

˜Correct flexion and extension of skull

˜Optimal exposure factors

Note: pituitary gland sits within the Sella Turcica

PA SKULL Projection

˜CR 0° exit at glabella

˜OML perpendicular to IR

˜MSP perpendicular to midline IR

˜NOSE & FOREHEAD against IR

Petrous ridges= where top of ear attaches to school

Evaluation Criteria:
PA SKULL
 0° to OML

˜Entire skull visualized

˜Demonstrates frontal bone

˜No rotation-equal distance bilaterally from lateral orbital margin to lateral cortex of skull

˜Petrous ridges superimpose superior orbital regions FILL orbits

˜Crista galli, great/less wings, ethmoid, SOM

NOTE-petrous ridge corresponds to level of external landmark of TEA

˜Raccoon Eyes or Raccoon Sign

ØBasal skull fracture-usually in the anterior cranial fossa

PA Axial Projection
CALDWELL

˜CR 15° caudad exit at nasion

˜OML perpendicular to IR

˜MSP perpendicular to IR

˜NOSE & FOREHEAD against IR

Evaluation Criteria:
PA 15° (Caldwell)

˜Entire skull visualized

˜Demonstrates frontal bone

˜No rotation-equal distance between lateral orbital margins to lateral cortex of cranium

˜Petrous ridges over lower ⅓ of orbits

˜Demonstrates Crista galli, ethmoid sinuses, petrous ridges, great/less wings sphenoid, dorsum sellae

SMV Projection

˜CR perpendicular to IOML and IR

˜CR 1½ inches inferior to mandibular symphysis

Evaluation Criteria: SMV

˜Entire skull visualized

˜Mandibular condyles anterior to petrous pyramids

˜No rotation or tilt

˜Optimal exposure factors

˜Demonstrates Occipital bone

AP Skull Projection
Trauma

˜CR parallel to OML

ØMay adjust CR 10-15˚ caudad

˜CR to glabella

˜MSP perpendicular to IR

Evaluation Criteria:
AP SKULL
 Trauma

˜Entire skull visualized

˜No rotation

˜Petrous ridges superimpose superior orbital regions FILL orbits

˜Optimal exposure factors

Same Criteria as PA Skull; orbits magnified

TRAUMA AP Axial Projection
 REVERSE CALDWELL

˜CR 15° cephalad to OML

ØFirst put CR parallel to OML then angle 15 degrees

˜CR to Nasion

Evaluation Criteria:
AP 15°Axial (Reverse Caldwell)

˜Entire skull visualized

˜No rotation

˜Petrous ridges over lower ⅓ of orbits

˜Optimal exposure factors

˜Trauma position; orbits considered magnified due to OID

Trauma position; same criteria as PA Axial Caldwell

Lateral Facial Bones
(SOI closest to IR)

˜CR perpendicular, centered to zygoma

Ø(boney arch of cheek formed by connection of zygomatic and temporal bones)

˜MSP parallel to IR

˜IPL perpendicular to IR

˜IOML perpendicular to front edge of IR

Evaluation Criteria:
Lateral Facial Bones

˜Zygomatic bones in center of radiograph

˜No rotation or tilt

˜Optimal exposure factors

˜Demonstrates superimposed great wings sphenoid, orbital roofs, mandible

Parietoacanthial (Waters) facial bones

˜MML perpendicular to IR

˜Chin against IR

CR perpendicular to IR to exit atacanthion

Erect Parietoacanthial (facial bones)

˜Horizontal CR

37°OML and IR (MML perpendicular to IR

Evaluation Criteria: Parietoacanthial
Waters facial bones

˜Petrous ridges below maxillary sinuses

˜No rotation

˜Optimal exposure factors

˜Demonstrates IOMS, maxillae, nasal septum, zygomatic bones, zygomatic arches, anterior nasal spine

PA Axial (Caldwell) facial bones

˜OML perpendicular to IR

˜Nose & Forehead against IR

˜CR 15° caudad, exits at nasion

Modified Parietoacanthial
(Modified Waters)

˜CR perpendicular, exits at acanthion

˜Chin and Nose against IR

˜LML perpendicular to IR

˜OML 55° angle to IR

˜Ideal projection to demonstrate possible orbital fractures and foreign bodies in the eye

Evaluation Criteria:
Modified Parietoacanthial

˜Petrous ridges projected in lower ⅓ of maxillary sinuses

˜Orbital floors not distorted thus demonstrates IOMs

˜No rotation

˜Optimal exposure factors

interpupillary line (IPL)

perpendicular line between pupils of eyes

Acanthiomeatal line (AML)

from acanthion to EAM

Mentomeatal line (MML)

from mental point (center of chin) to EAM

orbitomeatal line (OML)

from outer canthus to EAM

infraorbitalmeatal line (IOML)

from infraorbital margin to EAM

glabellomeatal line (GML)

from glabella to EAM