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