RAD-247 CH.11 POSITIONING CRANIUM & SKULL

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What is the routine for a cranium series
what are the special routines for a cranium series
- ap axial towne
- lateral
- PA 15 deg (caldwell) PA 25 deg or PA 0 deg
- PA axial (haas)
- SMV (submentovertex)
where is the cr for an ap axial (towne) method
how much is cr angle for both areas
- CR is 2.5 in above glabella
- CR 30 deg caudad to OML or 37 deg caudad to IOML
what lateral is required for a lateral skull
where is the cr for a lateral skull
- right lateral
- CR 2 in superior to EAM
In a rt lateral skull the MSP is parallel to what and the _____ is perpendicular to ______
- xray table
- interpupillary line
- table
When positioning and xraying the skull
what is the minimum SID and kv range
what size focal spot
- 40''
- 75-90 kv
- small FSS
in the ap towne axial method what must we ask the patient to do in order to get OML to perpendicular to the table
when a patient is unable to get the OML perp to the table what must you do instead
- depress the chin
- you must angle the tube 37 deg caudad and get the IOML perpendicular to the table and you can use a sponge if needed
what is the differences of degrees between the OML and the IOML

7-8 deg difference
what structures are visualized in the ap axial towne view

occipital bone petrous pyramids and foramen magnum are demonstrated with the dorsum sellae and posterior clinoids visualized in foramen magnum
what position is used to demonstrate air fluid levels in the sphenoid sinus which is a sign of a basal skull fx if intracranial bleeding occurs

cross table lateral
what is the position of the body in a right lateral skull position
what line must we align perpendicular to the table
Certain patients with broader shape may require what to get this position
- semi supine (or slight rao)
- interpupillary line
- a sponge to keep the head up
where is the cr exiting for a pa axial (caldwell) and what is the angulation of tube
Where does CR exit?
What line must be perp in this projection
what instructions will give the patient to acquire this position
- CR 15 deg caudad and centered to exit at the nasion
- OML
- tuck the chin towards your chest
what is the alternative method to the pa axial caldwell projection to allow better visualization of the superior orbital
where do u center
Where is the CR exiting
- pa axial with a 25-30 deg caudad angle
- center in same area so CR exits at the nasion and the OML is perp to the table
the pa axial caldwell 25-30 caldwell method where are the petrous ridges

petrous pyramids are projected at or below the IOM to allow visualization of the entire orbital margin
In the pa projection 0 degree where is the CR and is parallel to what?
where is it exiting and what is position of the patient
which line is perp to the table
- CR is perp to IR and parallel to OML and is centered to exit at the glabella
- the pt is face down with the chin tucked towrds chest
- OML
before doing and SMV projection special routing of the skull what must you rule out first

cervical spine fx or subluxation on trauma patients when attempting this position
where is the CR in an SMV projection

CR is perp to IOML and 1.5 inch below mandibular symphysis or midway between the gonions
Which line must be perp to the CR when doing the SMV
How do we achieve this position with the patient
- IOML
- ask patient raise the chin hyperextend the neck if possible until line is per to CR
Is the 10x12 cassette lengthwise or crosswise for an ap axial towne method
Which position of the skull requires the IR to be crosswise
- lengthwise
- right or left lateral skull
what position of the skull shows the petrous ridges over the lower 1/3 of the orbits

pa 15 deg caldwell
what causes the dorsum sellae to be projected above the foramen magnum in an ap towne axial view (2 things)

underangulation or insufficient flexion of the neck
over angulation of the CR or excessive flexion causes what in an ap town axial view

superimposes the posterior arch of C1 over the dorsum sellae w/in the foramen magnum which causes foreshortening of the dorsum sellae
what is the anatomy demonstrated in a right lateral skull

entire cranium with superimposed parietal bones entire view of sell turcica with anterior and posterior clinoids processes and dorsum sellae
In the pa axial caldwell 25-30 deg angle where are the petrous pyramids
Where is the cr
- projected at or just below the IOM
- centered to exit at the nasion
what alternative position is used for patients who cannot flex the neck efficiently for an ap towne view

pa axial (haas method)
In the pa haas method is the patient face down or face up
what line must be perp to IR
What is the angle of the tube
where is the CR and where does it exit
- face down
- OML
- 25 deg cephalad
- CR at level of EAM and exits 1.5 superior to nasion
which projection of the skull produces an image of the frontal bone with little or no distoretion

pa axial 0 deg cladwell
what positioning error is present if the petrous ridges are projected higher in the orbits than expected for a 15 deg pa axial projection

excessive flexion or insufficient CR angle
which positioning error has been committed if the EAMs are superimposed with on of them more superior than the other on a lateral skull

tilt of skull
superimposition of the posterior arch of C1 over the dorsum sellae w/in the
foramen magnum which causes foreshortening of the dorsum sellae is caused by what error in a townes view

overangulation of CR or excessive flexion of neck
No tilt is evident in an SMV projection of the skull by what

by the equakl distance between mandibular ramus and lateral cranial cortex
what anatomy is demonstrated in the pa axial haas method
No rotation is evident by what structures
- same as a townes
- symmetrical bilateral petrous ridges

Author

anatomy12

282507

Card Set

RAD-247 CH.11 POSITIONING CRANIUM & SKULL

Description

xray

Updated

2014-10-26T15:01:23Z

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