Skull- Positioning Q2; Facial, Orbits, and Sinuses

nasion

landmark to delineate skull and facial bones is the _______

• R and L Laterals

• Waters (parietocanthial)

• Modified Waters (parietoacanthial)

• PA axial (Caldwell)

Facial Bones Routine

Patient Position

• recumbent, upright

Part Position

• IOML parallel to floor or bottom of IR

Central Ray

• perp to IR

• enter zygoma half way btw outer canthus and EAM

Patient & part position, and Central Ray for lateral facial bones

• all bones of face including mandible

• no rotation or tilt

  • mandibular rami & sella turcica in profile, inf. and sup., orbital plates SI

Eval for lateral facial bones

• greater wings (sphenoid)

• orbital roofs

• sella turcica

• zygoma

• mandible

best demos for lateral facial bones

Patient Position

• prone or erect

• tip of extended chin on IR so MML is about perp to IR

Part Position

• OML 37° with plane of IR

Central Ray

• perp to IR

• exit at acanthion

positioning & central ray for Waters

• petrous ridges below maxillary sinuses

• orbits, maxillae, zygomas, zygomatic arches, foramen rotundum, nasal septum

Structures Shown in Waters projection

Patient Position

• prone, upright

Part Position

• extend neck so OML is 55° from plane of IR

• LML perp to IR

• MSP perp to IR

Central Ray

• perpendicular

• exits at acanthion

positioning and CR for Modified Waters

petrous ridges projected in lower 1/3 of maxillary sinuses

where are the petrous ridges located in a Modified Waters

• orbital floors

• blowout orbital fx

Best demoed in Modified Waters

Patient Position

• prone, upright

• Pt forehead & nose on IR

Part Position

• MSP perp to IR

• OML perp to IR

Central Ray

• 15° caudad

• exit at nasion

  • collimate to include above top of orbits thru jaw

positioning and CR for PA axial (caldwell) (facial bones)

• petrous ridges in lower 1/3 of orbits

• see orbits, maxillae, septum, zygoma, and ant. nasal spine

• no rotation

• optimal exposure factors

eval/structures for PA axial (caldwell) (facial bones)

30° caudal

angle for orbital rims (exaggerated Caldwell) to project petrous ridges below inferior margins of the orbits

• serve to aid in speech by resonation

• decrease weight of skull

• warm & moisten air

• shock absorbers

• control immune system

functions of sinuses

maxillary

sinuses that are aerated when born

6-7

frontal and sphenoidal sinuses develop by _____ years

18

ethmoid sinuses are fully developed by what age

• PA Caldwell

• Waters (Parietoacanthial)

• Lateral (affected side or bilat)

DO ALL UPRIGHT

paranasal sinus routine

75-85

kvp range for sinuses

Patient Position

• upright

Part Position

• IOML parallel to floor, collimate

Central Ray

• perp to IR

• enter 1/2’’-1’’ posterior to outer canthus

positioning and CR for lateral sinuses

• all 4 sinuses demonstrated

• cranium not rotated or tilted

• optimal exposure factors

eval for lateral sinuses

Patient Position

• upright

Part Position

• OML perp to IR

• IR tilted 15° OR OML 15° from horizontal (use sponge)

Central Ray

• horizontal

• exits nasion

• collimate

positioning and CR for PA Axial (Caldwell) sinuses

frontal & anterior ethmoid sinuses

what does the PA Axial (Caldwell) best demonstrate (sinuses)?

Patient Position

• upright

• hyperextend neck

Part Position

• MML perp to IR

• OML 37° with plane of IR

Central Ray

• horizontal

• enter parietal

• exit acanthion

positioning and CR for Waters (37°)

maxillary sinuses

what does the Waters (37°) best demonstrate?

• no rotation of cranium

• petrous ridges below maxillary sinuses

• optimal exposure factors

eval for Waters (37°)

Patient Position

• upright

Part Position

• IOML parallel to IR

Central Ray

• horizontal

• 3/4’’ anterior to level of EAM (between angles of mandible)

Positioning & CR for Sinuses - SMV

• mandibular condyles anterior to petrous ridges

• no rotation or tilt, correct collimation, optimal exposure factors

eval for sinuses- SMV

sphenoid sinus

what does the sinus- SMV best demonstrate?

37° medially

from the anterior rim, orbits are directed ___ _______ from MSP

30° superiorly

from the anterior rim, orbits are directed ____ ______ from OML

Patient Position

• prone, upright

Part Position

• OML perp to IR

Central Ray

• 30° caudad at MSP thru center of orbits

positioning and CR for metal screening (PA axial 30° caudad)

just below infraorbital margin

where are the petrous ridges in an metal screening

Patient Position

• prone, upright

• Pt forehead & nose on IR

Part Position

• OML 50° to IR

Central Ray

• perp at MSP thru midorbits

positioning and CR for Mod. Waters (orbits)

mid maxillary sinus

where are the petrous ridges in a Mod. Waters (orbits)

Patient Position

• recumbent, upright

Part Position

• IOML perp to front of IR

Central Ray

• perp to IR at outer canthus

  • collimate to improve contrast

positioning and CR for lateral orbits

Patient Position

• prone, upright

Part Position

• MSP 53° to IR

• AML perp to IR

Central Ray

• perp to downside orbit

positioning and CR for optic foramina (optional)