Measurements in Skeletal Radiology (Quiz 2)

Question 1

What is another name for basilar impression?

Answer 1

basilar invagination

Question 2

What is basilar impression?

test q

Answer 2

protrusion of odontoid process into foramen magnum

Question 3

What are the 2 types of basilar impression?

Answer 3

congenital or acquired

Question 4

What are the 3 congenital causes of basilar impression?

Answer 4

1) occipitilization (lacking space)
2) condylar hypoplasia (underdeveloped condyles)
3) achondroplasia (most common type of dwarfism)

Question 5

What are the 6 acquired causes of basilar impression?

Answer 5

1) paget’s disease
2) RA
3) osteomalacia
4) rickets
5) fibrous dysplasia
6) upper cervical trauma (MVA, falls, driving accident)

Question 6

What does PORT+ fd stand for?

Answer 6

bone softening conditions mneumonic
P= paget’s disease
O= osteoporosis and osteomalacia
R= RA
T= trauma
fd= fibrous dysplasia

Question 7

Black spinal fluid on MRI=

Answer 7

T1 weighted image/ hypointense signal

Question 8

White spinal fluid on MRI=

Answer 8

T2 weighted image/ hyperintense signal

Question 9

What are the 4 assessments to check for basilar impression?

Answer 9

1) basilar angle/ Welcker’s basilar angle/ Martin’s basilar angle
2) McGregor’s line
3) Chamberlain’s line
4) Macrae’s line/ Mcrae’s line/ foramen magnum line (FML)

Question 10

Which line assessments use a lateral skull/lateral cervical view?

Answer 10

1) basilar angle/ Welcker’s basilar angle/ Martin’s basilar angle
2) McGregor’s line
3) Chamberlain’s line
4) Macrae’s line/ Mcrae’s line/ foramen magnum line (FML)
5) method of bull
6) George’s line/ posterior vertebral alignment line/ posterior body line (PBL)
7) Cervical gravity line
8) Cervical lordosis/ angle of the cervical curve/ cervical lordotic angle
9) Eisenstein’s cervical method for sagittal canal measurement

Question 11

What is the procedure for a basilar angle assessment?

Exam 1 q

Answer 11

-3 points located and joined together by 2 lines
-the points used are the nasion, center of sella turcica, and basion (anterior margin of FM)

Question 12

What is the normal range for a basilar angle assessment?

Exam 1 q

Answer 12

123-152 degrees

Question 13

Increased basilar angle is associated with….

Answer 13

platybasia and potential basilar impression

Question 14

What is the procedure for McGregor’s line assessment?

Answer 14

-line drawn from posterior superior margin of hard palate to most inferior surface of occipital bone
-relationship of odontoid apex to line is assessed

Question 15

What is the normal measurement for McGregor’s line assessment?

Answer 15

odontoid apex should be above line no more than 8mm in males, 10mm in females

Question 16

What does it mean if McGregor’s line assessment has an abnormal superior position?

Answer 16

basilar impression

Question 17

Which line assessment is the most accurate/reproducible measure of basilar impression?

Answer 17

McGregor’s line assessment

Question 18

What is the procedure for Chamberlain’s line assessment?

Exam 1 q

Answer 18

-line drawn from posterior margin of hard palate to posterior aspect of foramen magnum (opisthion)
-relationship of odontoid apex to this line is assessed

Question 19

The posterior aspect of FM is called….

Answer 19

opisthion

Question 20

A line drawn from posterior margin of hard palate to opisthion is called?

Answer 20

Chamberlain’s line

Question 21

What is the normal measurement for Chamberlain’s line assessment?

Answer 21

tip of odontoid should NOT project above line, it may be up to 3mm above line

Question 22

What does it mean if Chamberlain’s line is >3 mm above odontoid tip?

Answer 22

possible basilar impression

Question 23

The anterior aspect of FM is called…

Answer 23

basion

Question 24

What are the other names for Macrae’s line?

test q

Answer 24

Mcrae’s line or foramen magnum line (FML)

Question 25

What is the procedure for Macrae’s line assessment?

test 1 q

Answer 25

-line drawn from basion to opisthion
-assess occipital bone and odontoid relative to line

Question 26

What is the normal measurement for Macrae’s line assessment?

Answer 26

-inferior margin of occipital bone should be at or below line
-a perpendicular line is drawn through the odontoid apex should intersect this line in its anterior quarter

Question 27

What does it mean if occipital bone is above Macrae’s line?

Answer 27

possible basilar impression

Question 28

What does it mean if the odontoid apex does not lie in the ventral quarter of Macrae’s line?

Answer 28

posterior displaced dens (due to dislocation of AO joint or fracture/dysplasia of the dens)