roentgenometrics Flashcards
what is the significance to a enlarged sella turcica
empty sella
tumor
normal
aneurysm
what is the max measurement for the sella turcica
16 x 12 mm across x depth
martins basilar line is drawn how
nasion to center of sella to the basion
what should the angle of the martins basilar angle line be
137 to 152 degrees
what does the martins basilar angle detect
if it is greater that 152 deg platybasia ( flat skull base)
how do you draw the chamberlains line
from hard palate to the opisthion
what are you measuring with the chamberlains line
the odontoid should not extend more than 7 mm above this line if it does that means that you have basilar invagination
how do you draw Mcgregor’s line
from the hard palate to the inferior occiput
what does mcgregor’s line tells us
the odontoid should not extend above this line by 8mm to 10 mm if it does it is basilar invagination
what causes basilar invagination
bone softening - pagets - osteomalacia - fibrous dysplasia arthritide - RA
what is the spinolaminar line
connecting the spinolaminar lines
what is George’s lines
the line that follows the posterior vertebral bodies
what does retrolisthesis mean
this is when georges line or the spinolaminar line do not line up from the vertebra above to the one below
what are some of the reasons for retrolisthesis
degenerative disc disease
fracture
dislocation
ligamentous laxity
what is the atlantodental interval
this is the measurement form the posterior surface of the anterior tubercle to the anterior surface of the odontoid (and you measure the small part
what is normal for the atlantodental interval
adult 3mm
child 5mm
consider flexion/extension
what is the atlantoaxial overhang sign
the lateral margin of the lateral masses of the atlas should not appear more lateral than the superior articular processes of the axis
what does atlantoaxial overhang sing tell us
lateral displacement suggest fracture
mild overhang a variant especially children
what are the angles for cervical lordosis
> 45 = hyperlordosis
< 35 hyperlordosis
35-45 normal
what is the cervical lordosis depth method
this is from the tip of the odontoid to the posterior surface of C7 this measure the depth at C4.
this should be an average of 8-12 mm
what is harrison posterior tangent method
on the lateral cervical projection, lines are drawn along the posterior body of C2
second line is drawn along the posterior body of C7 the superior or inferior angle of intersection is measured as the cervical lordosis
what is the average value of harrison posterior tangent method
the angle is 34 degrees with a standard deviation of 9 degrees
what is the ruth jackson stress line
line extending and intersecting from the posterior aspects of C2 and C7
the lines should intersect at C5/C6disc or facets on flexion
the lines should intersect at C4/C5 disc or facets on extension
what is the cervical gravitational line
from the odontoid tip
normally traverses the anterior-superior aspect of C7
