RAD112 Ch11 Skull and Sinuses Projections

AP Axial Skull Towne Method:

- Which positioning line is perpendicular to the IR

OML

AP Axial Skull Towne Method:

- for patients that are unable to flex the neck, which positioning line should you use to be perpendicular to the IR

IOML

AP Axial Skull Towne Method:

CR angle for the OML line

30º caudad

AP Axial Skull Towne Method:

CR angle for the IOML line

37º caudad

AP Axial Skull Towne Method:

Centering

2.5 inches above the glabella

AP Axial Skull Towne Method:

Why do we use the centering we use

to pass through the foramen magnum at the base of the occiput

AP Axial Skull Towne Method:

Which skull bone is best demonstrated

Occipital bone

AP Axial Skull Towne Method:

What is visualized in the shadow of the foramen magnum

Dorsum sellae and posterior chinois processes

AP Axial Skull Towne Method:

If the right petrous ridge is wider than the left, which way is the patient rotated

Rotated to the left

AP Axial Skull Towne Method:

What error is this?

- the Dorsum sellae is above the foramen magnum

Underangulation of CR

OR

Insufficient flexion of neck

AP Axial Skull Towne Method:

What error is this?

- the posterior arch of C1 is superimposed over the Dorsum sellae within the foramen magnum and produces foreshortening of the Dorsum sellae

Overangulation of CR

OR

Excessive neck flexion

AP Axial Skull Towne Method:

Shifting the anterior or posterior clinoid processes laterally within the foramen magnum indicates _________

Tilt

For a truama lateral skull, what projection is required

Horizontal beam projection

A horizontal beam projection (truama) skull demonstrates air-fluid levels in the _______ sinus

Sphenoid

Air-fluid levels in the sphenoid sinus is a sign of what type of fracture

Basal skull fracture if intracranial bleeding occurs

Lateral Skull:

- which lateral should you position the patient in?

the side of interest closest to IR

(Clinically/lab you'll do left lateral lol)

Lateral skull:

Which plane should be parallel to the IR

Midsagittal plane (MSP)

Lateral skull:

Which positioning line should be perpendicular to the IR

IPL

Lateral skull:

Adjust flexion to align _____ perpendicular to front edge of IR

IOML

Centering for lateral skull

2 inches superior to EAM

Lateral skull:

A patient with a broad chest may require a radiolucent spong under the ______ to prevent tilt

Head

Lateral skull:

A thin patient may require suppport under the ______

Thorax

Lateral skull:

Anterior and posterior separation of mandibular rami, greater wings of the sphenoid, or orbital plates indicates

Rotation

Lateral skull

Superior and inferior separation of the orbital plates of the frontal bones indicates

Til it

PA Axial Skull — 15º CR (Caldwell Method) or 25º to 30º CR:

Which positioning line should be perpendicular to the IR

OML

PA Axial Skull — 15º CR (Caldwell Method):

Centering and angle

15º caudad

Center to exit at nasion

PA Axial Skull — 25º to 30º (Caldwell Method) CR:

Centering and angle

25º to 30º caudad

Center to exit at nasion

PA Axial Skull — 25º to 30º CR:

Allows better visualization of

Superior orbital fissures

Foramen rotundum

Inferior orbital rim region

Decorated caudal angulation of the CR to 15º and/or increased neck flexion (chin down) for the PA Axial Skull (Caldwell method), will result in projection of the petrous puramids to the __________ of mid orbits

Lower 1/3rd

For patient who are unable to be positioned for PA projection (truama PTs) what projection can be used

AP axial with a 15º cephalic angle with OML perpendicualr to IR

For the PA Axial Skull Caldwell Method, if the distance between the right lateral orbit and lateral cranial cortex is greater than the left side, which way is the face rotated?

To the right

Petrous ridges are projected into the lower 1/3rd of the orbits. Which PA Axial Caldwell CR angle is this

15º

Petrous ridges are projected at or just below the IOM (below the orbits) to allow visualization of the entire orbital base. Which PA Axial Skull Caldwell CR angle is this

25º to 30º

Petrous ridges fill the orbits at the level of the supraorbital margin. Which position/projection is this

PA skull

Which skull projection demonstrates the frontal bone with minimal distortion

PA Skull

Which positioning line is perpendicualr to the IR for the PA Skull

OML

Centering for PA Skull

exit at glabella

How can you get the OML perpendicular to the IR

Have the patient place their forehead and nose against the IR

What needs to be ruled out before performing the SMV Skull projection

C-spine fracture or subluxation

Clinical indications for submentovertical Skull (2)

Advanced bony pathology of inner temporal bone structures

Basal skull fracture

For the SMV Skull, which positioning line is PARALLEL to IR

IOML

Part position for SMV skull

Hyperextend the neck

Raise the chin

Rest patients head on vertex

For the SMV skull, if the patient is unable to extend the neck sufficiently what can you do

Compensate by angling CR to remain perpendicular to IOML

IR may also be angled to maintain perpendicular relationship

Centering for the SMV skull

1.5 below mandibular symphysis

OR

Midway between gonions

Correct extension of neck and relationship between the IOML and CR for the SMV is indicated by the

Mandibular mental above the ethmoid sinuses

For the SMV skull, if the distance on the left side between the ramus and lateral cranium is greater on the left than the right, then the cranial vertex is

Tilted to the left

What is the alternative projection for patients who can't flex the neck sufficiently for the AP Axial Towne Method projection

PA Axial Haas method

The PA Axial Haas method results in magnification of the ___________ but in lower doses to facial structures and thyroid gland

Occipital area

Why is the PA Axial Haas method not recommended when the occipital bone is the area of interest

Bc of excessive magnification

For the PA Axial Haas method, which positioning line should be perpendicular to the IR

OML

CR angle for the PA Axial Haas method

25º cephalad to OML

Centering for the PA Axial Haas method

1.5 inches below the inion and exits 1.5 inches above the nasion

What is visualized in the shadow of the foramen magnum for the PA Axial Haas method

Dorsum sellae and posterior clinoid processes

No tilt of the PA Axial Haas method is indicated by correct placement of the _______ within the middle of the foramen magnum

Anterior clinoid processes

Should the patient be recumbent or erect for sinus projections

Erect to visualize air-fluid levels

If the patient was recumbent and stands up, how long should you wait for sinus airlfuid levels to settle

At least 5 minutes

If the patient is unable to be erect for sinus projections, what projection can you do

Horizontal beam

For the lateral sinuses, which positioning line is perpendicualr to the IR

IPL

For the lateral sinuses, adjust the chin to align _____ perpendicualr to the front edge of IR

IOML

What type of beam are you using for the lateral sinuses

Horizontal CR beam

Centering for the Lateral Sinuses

midway between outer canthus and EAM

Which sinuses are seen in the Lateral Sinuses projection

All 4

For Lateral Sinsues, anterior or posterior separation of mandibular rami and greater wings of the sphenoid indicates

Rotation

For Lateral Sinuses, superior and inferior separation of orbital plates and greater wings of sphenoid indicates

Tilt

For the PA Sinuses—Caldwell method, if possible, the IR should be angled how man degrees

15º

True or false, AEC is recommended for sinus projections

False, its not

For the PA Sinuses—Caldwell method, what is the positioning

OML 15º from horizontal

For the PA sinuses—Caldwell method, how can you get the OML 15º from horizontal

Have the PT place their forehead and nose against the board

Then extend neck 15º from the board

For the PA sinuses—Caldwell method, align CR ________, parallel with floor

Horizontal

Centering for PA Sinuses—Caldwell method

Center CR to exit at nasion

If the IR can be tilted 15º for the PA Sinuses Caldwell method, how should the PT be positioned

OML perpendicualr to IR and 15º to horizontal CR

Which sinuses are best seen in the PA SInuses Caldwell method

Frontal and ethmoid

Correct alignment of OML and CR of the PA Sinuses—Caldwell method demonstrates the petrous ridges into _______ of orbits

Lower 1/3rd

For the parietoacantial sinsues—waters method, how do you position the PT

Extend the neck

Place the chin and nose against IR

For the parietoacanthial sinsues—waters method, which positioning line is perpendicular to IR

MML

For the parietoacanthial sinsues—waters method, the OML forms a ____º angle with plane of IR

37º

Centering for the parietoacanthial sinsues—waters method

Center to exit at a anthill

Which sinuses are best demonstrated for the parietoacanthial sinsues—waters method

Maxillary sinuses

Frontal sinuses (oblique view)

Adequate extension of the neck for the parietoacanthial sinsues—waters method demonstrates petrous ridges....

Below maxillary sinsues

Patient position for the SMV Sinuses

Raise chin

Hyperextend neck if possible

Head rests on vertex of skull

Which positioning line is parallel to the IR for the SMV sinuses

IOML

If the PT is unable to extend the neck sufficiently for the SMV sinsues, what can you do

Angle the tube from horizontal as needed to align CR perpendicular to IOML

Centering for the SMV sinsues

Midway between angles of mandible at level 1.5 to 2 inches below mandibular symphysis

Which sinsues are best demonstrated for the SMV Sinsues projection

Sphenoid

Ethmoid

Maxillary sinuses

Correct extension of neck and relationship btwn IOML and CR for the SMV Sinsues is indicated by

Mandibular mental anterior to ethmoid sinuses

Which projection is a good alternative to demonstrated the sphenoid sinuses for PTs who can't perform the SMV Sinuses projection

Parietoacanthial transoral Sinsues—Opoen-mouth waters method demonstrates

PT position for the parietoacantial transoral Sinsues—open-mouth waters method

Extend neck

Place chin and nose against IR

You should adjust the head for the Open-Mouth Waters Method for Sinsues until the ____ forms a ____º angle with the IR

OML forms a 37º angle with IR

For the parietoacantial transoral Sinsues—Open-mouth waters method, which positioning line is perpendicular to the IR with the mouth CLOSED

MML

After the MML is perpendicular to the IR for the parietoacantial transoral Sinuses—Openmouth Waters Method, instruct the patient to...

Open the mouth

The MML may not be perpendicular after this

Centering for the Parietoacanthial transoral Sinuses—Open-Mouth waters method

Center to exit at acantion

Which sinsues are best demonstrated for the Parieotacanthial transoral sinsues—Open-mouth waters method

Maxillary sinsues

Oblique view of frontal

Sphenoid visualized through open mouth

For the parietoacanthial transoral Sinsues—Open-mouth waters method, which sinus is seen through the open mouth

Sphenoid

For the parietoacanthial transoral Sinsues—Open-mouth waters method, the petrous ridges are visualized....

Inferior to the maxillary sinsues