RADT 211 EXAM #3 - THEORY

List the FACIAL BONES

• maxillae (2)

• zygoma (2)

• lacrimal (2)

• nasal bones (2)

• palatine (2)

• inferior nasal conchae (2)

• vomer

• mandible

What are the only SINGLE facial bones

vomer and mandible

What are the 4 PROCESSES of the MAXILLAE

• frontal process

  • meets with the frontal bone

• zygomatic process

  • meets with the zygoma

• alveolar process

  • teeth embedded into this area

• palatine process

  • inferior surface

  • hard palate / roof of mouth area

  • meets with palatine bone

What are the 3 PROCESSES of the ZYGOMA

• frontal process

  • meets with the frontal bone

• maxillary process

  • meets with the maxilla

• temporal process

  • meets with temporal bone

  • forms zygomatic arch

What is a TRIPOD fracture

• direct trauma to the zygoma

• becomes free floating

• zygoma separates from all 3 bones it articulates with

What are the 2 PARTS of the palatine bone

• vertical part

• horizontal part

  • on hard palate area

  • pterygoid hamuli off sphenoid are visible on external corners

The VOMER makes up the __________ with the perpendicular plate of the ethmoid bone

bony nasal septum

What is the FACIAL BONE routine

• Basic

  • PA Axial (Caldwell)

  • lateral

  • parietoacanthial (Waters)

• special

  • modified parietoacanthial (modified Waters)

  • screening views for MRI

What are the TECHNICAL CONSIDERATIONS for facial bones positioning

• erect preferred (only do recumbent if trauma or unable)

  • air-fluid levels are visible

• 65-80 kVp

• utilize grid (EXCEPT for nasal bones)

• small focal spot

• 40-inch SID

• remove all metal/artifacts from ears, head, face, mouth and neck

Describe PA AXIAL CALDWELL facial bones POSITIONING

• OML perpendicular

• MSP perpendicular

• angle tube 15 degrees caudal

• raise OML 15 degrees to IR

• CR exiting at nasion

Describe PA AXIAL CALDWELL facial bones CRITERIA

• petrous ridges projected into lower 1/3 of orbits

• visualizing bony nasal septum best

• no rotation

Describe LATERAL facial bones POSITIONING

• radiograph side of interest

• IPL perpendicular to IR

• MSP parallel to IR

• IOML plane perpendicular to front edge or parallel to top edge of IR

• CR perpendicular, centered to zygoma

Describe LATERAL facial bones CRITERIA

• zygomatic bones in center of radiograph

• no rotation or tilt

• optimal exposure factors

• include mandible

Describe PARIETOACANTHIAL (WATERS) facial bones POSITIONING

• horizontal CR

• PA

• MSP perpendicular

• raise OML to form 37 degree angle to IR

• MML should be perpendicular to IR

• CR exit at acanthion

Describe PARIETOACANTHIAL (WATERS) facial bones CRITERIA

• petrous ridges BELOW maxillary sinuses

• no rotation (orbits equal distance)

• optimal exposure factors

Describe ACANTHIOPARIETAL (REVERSE WATERS) facial bones POSITIONING

• done when you can’t do AP

• MML needs to be perpendicular

• CR perpendicular to the plane of MML (angle tube to match)

What radiographs are done to visualize the NASAL BONES

• Waters

• bilateral nasal bones

Describe LATERAL NASAL BONES POSITIONING

• recommended to do both laterals

• NO GRID

• use lower kVp

• IPL perpendicular to IR

• MSP parallel to IR

• IOML parallel to top edge or perpendicular to side edge of IR

• CR perpendicular, centered to ½ inch inferior to nasion

Describe LATERAL NASAL BONES CRITERIA

• include from nasal suture to anterior nasal spine

• no rotation

• optimal exposure factors

• close collimation

Describe ORBIT ORIENTATION

• cone-shaped

  • starts wider at the base

  • narrows down while moving posterior towards apex

• 30 degrees SUPERIOR angle as orbits go posterior

• 37 degrees MEDIAL angle as orbits go posterior

• the long axis of the orbits project both upward and toward the midline

What makes up the BASE of the ORBIT

• frontal (orbital plate)

• zygoma

• maxilla

What anatomy makes up the OPENINGS in the ORBIT

• optic foramen (at apex)

• sphenoid strut

• superior orbital fissure

• inferior orbital fissure

List the bony composition of ORBITS (7 TOTAL)

• cranial bones (3)

  • ethmoid

  • frontal (base)

  • sphenoid

• facial bones (4)

  • lacrimal

  • maxillary (base)

  • palatine

  • zygomatic (base)

List the SEQUENCE of the bony composition of the ORBITS

• sphenoid

• palatine

• ethmoid

• lacrimal

• maxilla

• frontal

• zygoma

What is a BLOWOUT fracture

• blunt trauma to the eye to the point that the pressure inside the eye causes the orbital floor to collapse

• bones separate and collapse at base

• look for teardrop sign on radiograph (seen on superior portion of maxilla)

What is the ORBIT/OPTIC FORAMINA routine

• Basic

  • Parietorbital oblique (Rhese)

  • Parietoacanthial (Waters)

  • PA (Caldwell)

• Special Views

  • modified Waters

Describe PARIETOORBITAL OBLIQUE (RHESE method) POSITIONING

• bilateral projections taken for comparison

• rotate head 37 degrees toward affected side

  • orbits have a 37-degree medial alignment, rotating head compensates

• 3-point landing = chin, cheek, and nose

• MSP forms 53 degree angle to IR

• AML perpendicular to IR

• CR perpendicular to downside orbit

• utilize grid (75-85 kVp)

Describe PARIETOORBITAL OBLIQUE (RHESE method) CRITERIA

• optic foramen should be visualized in lower lateral quadrant

  • lower outer quadrant

Describe MODIFIED WATERS positioning for ORBITS

• raise OML to form a 55 degree angle to IR

• LML / MSP perpendicular to IR

• CR perpendicular, exiting at acanthion

• ideal projection to demonstrate possible orbital fractures and foreign bodies in the eye

Describe MODIFIED WATERS CRITERIA for ORBITS

• petrous ridges projected in lower ½ of maxillary sinuses

• orbital floors not distorted

• no rotation

• optimal exposure factors

Describe ZYGOMATIC ARCH anatomy

• maxilla has temporal process

• meets with temporal bone’s zygomatic process

What is the ZYGOMATIC ARCH routine views

• Basic

  • Submentovertex (SMV)

  • oblique inferosuperior (tangential)

  • AP axial (modified Towne)

• special

  • commonly part of facial bone study

  • parietoacanthial (Waters)

  • lateral

Describe SMV POSITIONING

• CR perpendicular to IOML

• IOML is parallel to IR (bend head way back)

• bilateral zygomatic arches

Describe SMV CRITERIA

• zygomatic arches well demonstrated in profile and symmetric

Describe OBLIQUE INFEROSUPERIOR (tangential) POSITIONING (zygomatic arch)

• start in SMV position (IOML parallel to IR)

• rotate AND tilt skull 15 degrees toward affected side

• CR perpendicular to IR and IOML

• CR to arch of interest

Describe AP AXIAL (MODIFIED TOWNES) POSITIONING (zygomatic arch)

• have patient tuck chin down

• OML perpendicular to IR = 30 degrees caudal

• settle for IOML perpendicular to IR = 37 degrees caudal

• CR 1 inch superior to nasion (to pass through mid arches)

Describe AP AXIAL (MODIFIED TOWNES) CRITERIA (zygomatic arch)

• bilateral zygomatic arches centered

• no rotation

• optimal exposure factors

The mandible must be included on the facial bone radiographs (T/F)

TRUE

An erect position is preferred for facial bone radiographs if the patient has had a direct hit to their face; if not, the patient can be positioned either erect or recumbent (T/F)

FALSE

• always try to position erect

On a parietoacanthial radiograph, the petrous pyramids will be located _______________

BELOW the maxillary sinuses

All of the following anatomy can be visualized on a WATERS view EXCEPT:

• nasal spine

• bony nasal septum

• zygomatic arches

• maxilla/maxillary sinus

nasal spine

What is the only movable facial bone

mandible

The nasal bone and lacrimal bone are the smallest facial bones (T/F)

TRUE

The CR for MODIFIED PARIEOTACANTHIAL view exits the lips (T/F)

FALSE

The PARIETOACANTHIAL radiograph would best be utilized for visualization of the __________

bony nasal septum

What SKULL BONES do the MAXILLAE articulate with

• frontal

• ethmoid

What SKULL BONES do the ZYGOMA articulate with

• frontal

• temporal

What SKULL BONES do the LACRIMAL bones articulate with

• frontal

• ethmoid

What SKULL BONES do the NASAL bones articulate with

• frontal

• ethmoid

What SKULL BONES do the INFERIOR NASAL CONCHAE articulate with

• ethmoid

What SKULL BONES does the VOMER articulate with

• sphenoid

• ethmoid

What SKULL BONES does the MANDIBLE articulate with

• temporal

What FACIAL BONES do the MAXILLAE articulate with

• opposite maxillae

• zygoma

• lacrimal

• nasal

• palatine

• inferior nasal conchae

• vomer

What FACIAL BONES do the ZYGOMA articulate with

• maxillae

What FACIAL BONES do the LACRIMAL bones articulate with

• maxillae

• inferior nasal conchae

What FACIAL BONES do the NASAL bones articulate with

• maxillae

• opposite nasal bone

What FACIAL BONES do the INFERIOR NASAL CONCHAE articulate with

• maxillae

• inferior nasal conchae

• vomer

• opposite palatine

What FACIAL BONES do the VOMER articulate with

• right maxillae

• left maxillae

• palatine

What are the TWO PORTIONS of the MANDIBLE

• ramus

• body

• they are separated by the angle of the mandible (gonion)

What ANATOMY makes up the RAMUS of mandible

• coronoid process

• condyloid process

• condyle (head)

• neck

• mandibular notch

• more vertical position

What ANATOMY makes up the BODY of mandible

• mental foramen

• mentum/mental protuberance

• symphysis mentum

• mental point (center of mentum)

• alveolar process

• more horizontal position

Describe the TEMPOROMANDIBULAR JOINT (TMJ)

• only movable joint in the skull

• located anterior and slightly superior to the EAM

Describe the ARTHROLOGY of the ALVEOLI AND TEETH

• synarthrodic articulations

• have fibrous structure

• gomphosis subclass

Describe the ARTHROLOGY of the TMJ

• diarthrodic articulation

• bicondylar (gliding and hinge) movement

• synovial structure with a fibrous disk

What is the MANDIBLE routine

• basic

  • axiolateral oblique

  • PA - 0 degrees

  • PA or AP axial for condyles

• special

  • SMV

  • panorex - know only IOML

Describe AXIOLATERAL OBLIQUE mandible POSITIONING (minimizing superimposition)

to minimize superimposition of the opposite body

• utilize combo of tilt of head and CR angle (not to exceed 25 degrees)

  • e.g. angle CR 10 degrees and tilt head 15 degrees

• OR utilize a 25 degree cephalic angle toward the IR with NO head tilt

Describe AXIOLATERAL OBLIQUE mandible POSITIONING (avoiding distortion of area of interest)

• Ramus = head in TRUE lateral

• Body = 30-degree rotation of head TOWARD IR

• Mentum = 45-degree rotation of head TOWARD IR

• General Survey of Mandible = 10-15 degrees rotation of head TOWARD IR

Describe AXIOLATERAL OBLIQUE mandible CRITERIA

• side of interest and part of interest well visualized without superimposition of opposite side

For a TRAUMA mandible, how would you position the AXIOLATERAL OBLIQUE

• horizontal beam

• CR 25 degrees no tilt

Describe PA MANDIBLE POSITIONING

• OML perpendicular to IR

• MSP perpendicular to IR

• CR perpendicular and exiting at lips

• best demonstrates rami and lateral portion of body

Describe PA MANDIBLE CRITERIA

• mentum and body visualized

• best demonstrates rami and lateral portion of body

• entire mandible included

• no rotation

• optimal exposure factors

Describe AP AXIAL TOWNES for mandible or TMJ POSITIONING

• done to visualize condyles

• CR 35 degrees if OML perpendicular to IR

• CR 42 degrees if IOML perpendicular to IR

• CR 1 inch superior to glabella

How would you position an AP AXIAL TOWNES for mandible/TMJ visualization if pt is PA

20-25 degrees cephalic, exit at acanthion

Describe AP AXIAL TOWNES for mandible/TMJ CRITERIA

• condyloid processes demonstrated and symmetric

• no rotation

• optimal exposure factors

What is a PANOREX

• visualizes teeth and alveolar regions

• IOML parallel to floor

What is the TMJ routine

• Basic

  • AP axial Townes

  • Axiolateral 15 degree oblique (modified Law)

    • OR

  • Axiolateral (Schuller)

• ALL TMJ imaging performed bilateral with both open and closed projections

Describe AXIOLATERAL OBLIQUE (MODIFIED LAW METHOD) for TMJ POSITIONING

• bilateral projections

• one image opened mouth, one image closed mouth

• lazy lateral position

• MSP NOT parallel to IR

• IPL perpendicular to IR

• IOML perpendicular to IR

• rotate MSP 15 degrees toward IR

• CR angled 15 degrees caudad

• CR 1 ½ inches SUPERIOR to upside EAM

• visualizes DOWNSIDE

Describe AXIOLATERAL OBLIQUE (MODIFIED LAW METHOD) for TMJ CRITERIA

• TMJ closest to IR demonstrated

• open and closed mouth projections

• optimal exposure factors

Describe AXIOLATERAL (SCHULLER METHOD) for TMJ POSITIONING

• bilateral projections

• one image opened mouth, one image closed mouth

• TRUE lateral position

• MSP parallel to IR

• IPL perpendicular to IR

• IOML perpendicular to front edge of IR

• CR angled 25-30 degrees caudad

• CR enters ½ inch anterior and 2 inches superior to upside EAM

Describe AXIOLATERAL (SCHULLER METHOD) for TMJ CRITERIA

• TMJ closest to IR demonstrated

• optimal exposure factors

How much must the skull be rotated from a lateral position to best demonstrate the body of the mandible for the axiolateral oblique projection?

30 degrees

How much is the CR angled for an AP axial projection of the mandible if the IOML is perpendicular to the IR

42 degrees

What type of CR angle is required for the axiolateral (Schuller method) for the TMJs

25-30 degrees caudad

What is the name of the process of the mandible in which the lower teeth are embedded

Alveolar process