Radiographic Positions and Projections

Lateral Facial Bones

10x12 LW 40" SID CR perpendicular CR to zygoma, halfway between outer canthus and EAM Small focal spot as opposed to other facial bones positioning Side of interest closest to IR

AP Reverse Caldwell Skull (Trauma)

15 degree cephalad to OML- centered to nasion

CR for AP Axial Towne

30 degree caudal to OML 37 degree caudal to IOML 2 1/2" (6.5cm) above glabella

AP Axial (Towne)

80 20 30 degree caudad to OML chin depressed 37 degree caudad to IOML no depression CR 2 1/2" above glabella

PA Axial (Haas)

80 20 OML perpendicular IR, 25 degree cephalad to OML CR to MSP pass through level of EAM exit 1 1/2" (4cm) sup to nasion (can't do AP towne, magnifies occipital region but lower thyroid dosages)

Glabella

A single bony prominence of the frontal bone located between the superciliary arches in the inferior part of the frontal bone above the root of the nose.

AML

Acanthiomeatal line

PA Axial Caldwell Skull

CR 15 degrees caudad to OML, exit at nasion *Alternate Angle*: (Best demonstrates orbital margins) - OML perpendicular - CR 25-30* caudad exiting at Nasion

PA AXIAL FACIAL (CALDWELL)

CR 15 degrees caudal to OML, centered to exit at nasion A 30 degree CR angle is required to project petrous ridges below lower orbital margins if this is an area of interest CR will exit level of misorbits

AP Axial (Towne) Trauma

CR 30 degree caudad to OML- CR to 2.5" above glabella

Lateral cranium CR

CR perpendicular to IR, 2" (5cm) superior to EAM

PA cranium

CR: centered to the glabella SID: 40 inches mAs: phototime center cell kVp: 75 10X12 OML perpendicular to IR hold breathe

Lateral Cranium anatomy demonstrated

Entire cranium visualized and superimposed cranial halves, entire sella turcica and dorsum sellae No tilt evident by superimposition of orbital plates (roofs) No rotation evident by superimposition of greater wings of sphenoid and mandibular rami

SMV Cranium anatomy demonstrated

Foramen ovale and spinosum, mandible, sphenoid and posterior ethmoid sinuses, mastoid process, petrous ridges, hard palate, foramen magnum, and occipital bone Mandibular condyles are anterior to the petrous portion of temporal bone No tilt equal distance between mandibular condyles and lateral skull No rotation evident MSP parallel to edge of radiograph

PA Cranium anatomy demonstrated

Frontal bone and crista galli demonstrated without distortion Petrous ridges at level of superior orbital margin

PA Axial Cranium (Caldwell) anatomy demonstrated

Greater/lesser wings of sphenoid, frontal bone, and superior orbital fissures Petrous ridges in lower 1/3 of orbits

Submentovertical (SMV) Cranium

Hyperextend neck to place IOML parallel to IR CR angled to be perpendicular to IOML, centered .75" (2cm) anterior to level of EAMS (midpoint between angles of mandible)

Parietoacanthial modified waters anatomy demonstrated

Inferior orbital floors in profile (undistorted) Ideal projection to demonstrate possible "blow out" fractures of orbital floor Petrous ridges projected in lower 1/2 of maxillary sinuses.

IOML

Infraorbitomeatal Line (Reids base line)

What positioning line is used for modified waters?

LML

Parietoacanthial modified waters facial bones

LML is perpendicular to IR which places OML 55 degrees to IR

What positioning line is used for Waters?

MML

Parietocanthial (Waters) Facial Bones

MML perpendicular to IR which places OML 37 degrees to IR CR perpendicular to exit at acanthion

Angle (gonion)

Masseter muscle attaches here

Acanthion

Midline point at the junction of the upper lip & nasal septum (where nose & upper lip meet)

What best shows blow out fracture?

Modifed Waters

Anatomy demonstrated on AP Axial (Towne Method)

Occipital bone, petrous pyramids, and foramen magnum Dorsum sellae within foramen magnum No rotation evident by symmetry of petrous pyramids of temporal bones

PA Axial facial (Caldwell) anatomy demonstrated

Orbital rims, maxillae, nasal septum, and zygomatic arches Petrous ridges in lower 1/3 of orbits

PA Axial (Caldwell) Cranium Position

Patients forehead and nose resting on tabletop, OML perpendicular to IR

Lateral Facial Bones anatomy demonstrated

Superimposed facial bones, greater wings of shpenoid and sella turcica Region from orbital roofs to mentum demonstrated No tilt evident by superimposition of orbital plates (roofs) No rotation evident by superimposition of greater wings of sphenoid and mandibular rami

interpupillary line

a line used in positioning to ensure that the skull is in a true lateral position

Nasion

bridge of nose

Mental point

center of mental protuberance

Supraorbital groove

corresponds to the highest level of the facial bone mass

Inion

external occipital protuberance

Parietoacanthial waters facial bones anatomy demonstrated

general survey of facial bones, inferior orbital rims, maxillae, and nasal septum Petrous ridges just inferior to floor of maxillary sinuses

GAL

glabelloalveolar line

GML

glabellomeatal line

LML

lips-meatal line

MML

mentomeatal line

OML

orbitomeatal line

In the Lateral Cranium projection, the MSP is ___ to the IR, the IOML is _____ to the IR's front edge or ____ to transverse plane, and the IPL is ____ to the IR.

parallel, parallel, perpendicular

What are the most common positioning errors for cranial and facial bone radiography?

rotation, tilt, flexion, and extension

superciliary arch

the ridge above the eye socket indicating the location of the frontal sinus