Rads 1120: Skull/ Sinus Proceedures

MSP

1

Top of ear attachment

1

Outer Canthus

10

Glabella

2

Glabelloaloviolar line

2

On the AP axial (Towne) projection of the skull, if the IOML is perpendicular to the IR, the central ray is directed:

2 1/2 inches above the glabella at a caudal angle of 37 degrees passing through at the level of EAM, exiting the foramen magnum.

Glabella

3

Interpupilary Line

3

IOML or OML base line: Ap Axial (Towne) with 30 degree caudal angle

30 degree: OML 37 degree: IOML

Inner Canthus

4

Nasion

4

Acanthion

5

Nasion

5

Acanthion

6

Mental Point

6

Angle of mandible

7

Mental Point

7

There is a ______ degree difference between OML and IOML.

7

Angle of Mandible

8

EAM

8

Auricle

9

Infraorbital margin

9

Glabellomeatal Line GML

A

Towne

AP Axial skull projection 30 degree caudad

Describe inner canthus:

Angle at inner corner of eye

Describe outer canthus:

Angle of outer corner of the eye

Orbitomeatal Line OML

B

Describe Submental point:

Below the chin

Baseline: Interpupillary Line:

Between pupils of both eyes.

Describe alveolar process:

Bottom of maxillae bone, directly superior to teeth.

Describe acanthion

Bottom underneath where nose meets the face

Infraorbital meatal line IOML

C

Hyposthenic patients may need ___________ elevated.

Chest

Acanthionmeatal line AML

D

Mentomeatal Line MML:

E

Describe EAM:

External Auditory Meatus

Describe supercilliary arches

Eyebrows

Baseline: Acanthiomeatal line;

From acanthion to EAM

Baselines: Glabellomeatal line:

From glabella to EAM

Baseline: Glabello-alvolar Line

From glabella to alveolar process

Baselines: Infraorbitalmeatal Line IOML:

From infraorbital margin to EAM

Baseline:Mental-meatal Line:

From mental point to EAM

Don't forget, the __________is attached to the body.

Head

Hypersthenic patients may need ______________ elevated.

Head

What will happen to a sinus radiograph that is overpenetrated:

High levels of kVp can diminish or obliterate existing pathologic conditions.

If fluid is present in the sinuses and the patient is radiographed in a recumbent position with a vertical beam, the resultant radiograph will demenstrate:

Homogeneous density throughout the cavity, with no evidence of a fluid level.

What is the centering point for a lateral projection of the paranasal sinus:

Horizontal entering patients head 1/2 to 1 inch posterior to the outer canthus.

Where is the CR directed an a lateral skull:

Horizontal, entering 2 inches superior to the EAM.

IOML or OML base line: Lateral Sinus

IOML

IOML or OML base line: Lateral Skull

IOML

IOML or OML base line: SMV Sinus

IOML

IOML or OML base line: SVM Skull

IOML

On a lateral skull radiograph, which baseline is perpendicular to the IR:

IOML

The central ray is directed to the __________ baseline for the SMV projection of the sinuses.

IOML

Of the sinuses, which will the parieto-canthial (Waters) projection best demonstrate:

Maxillary sinuses, if open mouth also the sphenoid.

Describe: Mental Point:

Mid-line of the tip of the chin

Describe Nasion:

Midline of nasofrontal suture

When the body is not correctly adjusted, it puts strain on _____________ and they cannot support the ____________.

Muscles, position

IOML or OML base line: PA Skull

OML

IOML or OML base line: PA axial (Hass) Skull

OML

IOML or OML base line: Pa Axial (Caldwell) Skull

OML

The frontal sinuses will best be demonstrated with what projection:

PA Axial (Caldwell) projection

Haas

PA Axial skull projection 25 degree cephalic

Caldwell

PA axial skull projection 15 degree caudad

The patient is erect facing the vertical grid device. The chin is extended so that the OML forms a 37 degree angle with the plane of the film. The central ray is directed perpendicular to exit the acanthion. Describe the resulting radiograph evaluation:

Parietocanthial Projection Waters Method

Which projection would best demonstrate the sphenoid sinus:

Parietocanthial projection Waters method, open mouth

Describe Auricular point

Part of the external ear that projects posterior and leads to EAM.

Where is the central ray directed on a PA projection of the skull:

Perpendicular to exit at the nasion.

On a right lateral position of the skull, how is the IOML positioned:

Perpendicular to the front edge of the IR, and parallel to the long axis of the IR.

On a PA projection of the skull on a trauma patient who must remain immobilized is done with the patient in what position:

Recumbent PA

Describe Infraorbital margin:

Ridge below the orbit

Uncomfortable body positions cause ____________ or other motion and _____________.

Rotation, repeats

The ______ projection will demonstrate the ethmoid air cells best.

SMV

Describe the size shape and placement of: Maxillary

Size: Largest but Very in size Shape: Look rectangular but, pyramidal-shaped with 3 walls Placement: Maxillary bone

Describe the size shape and placement of: Frontal sinuses

Size: Second largest Shape: Pyramid-shaped Placement:within frontal bones between tables of bone.

Describe the size shape and placement of: Sphenoid

Size: Vary not usually symmetric Shape: paired but can be only one Placement: Sphenoid bone below cella turcica

Describe the size shape and placement of: Ethmoid

Size: vary Shape:vary Placement: In labyrinths of ethmoid bones: Anterior, middle, posterior

Define Dolichocephalic:

Skull Morphology: #Long from front to back #Narrow side to side #Deep vertex to base #Petrous pyramids 40 degrees from MSP. #Internal structures lower

Define Mesocephalic:

Skull Morphology: #Typical Shape #Petrous pyramids are 47 degrees from MSP #Superior boarders of these are at the base of the cranium

Define brachycephalic:

Skull morphology: #Short from front to back #Broad from side to side #Shallow vertex to base #petrous pyramids are 54 degrees from MSP #internal structures are higher

Describe glabella:

Smooth area between supercilliary arches

Describe Vertex:

Top of the head

when doing an SMV on a patient that cannot extend their head back far enough to place the IOML parallel with the film how would you angle to compensate:

Use an angle to stay perpendicular to IOML

You are performing a recumbant lateral skull on a hyposthenic patient. The patients body is in an LAO position so you can get a left lateral position of the skull. You notice the mid-sagittal plane is not parallel with the table, being lower at the mental point than the vertex. To aid in correct positioning you must:

elevate the chest

Baselines: Orbitalmeatal line OML:

from outer canthus to EAM

To check accuracy of positioning on the parieto-acanthial (Waters) projection, the petrous ridges should be:

immediately below maxillary sinuses