Lecture 6: MSK Imaging 1 - Imaging Principles and Back

Question 1

What are important features of vertebrae?

Answer 1

vertebral body, pedicles, transverse processes, inferior / superior articular processes, laminae, spinous process

Question 2

What are the characteristics of a typical cervical vertebra?

Answer 2

small anterior vertebral body, transverse processes which possess transverse foramina and uncinate processes

Question 3

Which cervical vertebrae are atypical?

Answer 3

C1 and C2

Question 4

What are the characteristics of C1?

Answer 4

C1 does not have a vertebral body or anterior / posterior arches which associate with anterior / posterior tubercles
laterally articulates with the occipital bone above and C2 below

Question 5

What are the characteristics of C2?

Answer 5

C2 has an odontoid process which protrudes above and acts as the vertebral body of C1

Question 6

Which ligaments extend from the upper part of the odontoid process to the inner part of the foramen magnum?

Answer 6

the alar ligaments

Question 7

Which ligament extends superiorly and inferiorly from the odontoid process?

Answer 7

the longitudinal band of the cruciform ligament

Question 8

What is the role of the much larger transverse band of the cruciform ligament?

Answer 8

has a higher importance in holding the dens stable

Question 9

What are the five major densities on X-ray and CT?

Answer 9

metal: white
bone: light grey
soft tissue: grey
fat: dark grey
air: black

Question 10

What is the difference between T1 and T2 MRIs?

Answer 10

in T1 MRIs fluid is dark, whereas in T2 MRIs fluid is bright

Question 11

What are the three major views of a plain radiograph?

Answer 11

anterior-posterior (AP)
lateral
peg / odontoid view

Question 12

What is the supplementary view of a plain radiograph?

Answer 12

oblique

Question 13

How is a normal cervical spine identified using AP and lateral views?

Answer 13

checking the structure and alignment of anterior, posterior and lateral projections

Question 14

How is a normal cervical spine identified using a peg view?

Answer 14

checking that the lateral processes of C1 and C2 line up and assessing that the dens is midline between the lateral masses of C1 and that the space between each of the lateral masses at the dens is the same on either side

Question 15

How is a normal cervical spine identified using an oblique view?

Answer 15

checking for normal neural foramina

Question 16

What causes Hangman’s fracture?

Answer 16

bilateral pars or pedicle fracture

Question 17

How can a Jefferson fracture be identified?

Answer 17

C1 burst fracture

very large discrepancy in how far the lateral masses are from the dens

Question 18

How can an anterior longitudinal ligament disruption be identified?

Answer 18

the dark line of the anterior longitudinal ligament disappears at level C6-C7 in this case and reappears further down

Question 19

What causes disruption of the anterior longitudinal ligament?

Answer 19

hyperextension

Question 20

What are important things to look out for when diagnosing an injury to the spine?

Answer 20

normal alignment of vertebral bodies
even spacing between the pedicles
normal alignment of spinous processes

Question 21

What are the Denis spinal columns and how can they be used to determine the severity of a spinal fracture?

Answer 21

anterior, middle and posterior columns
fracture of a single column is stable
fracture of two columns may be stable or unstable
fracture of three columns is unstable

Question 22

What is the anterior Denis spinal column?

Answer 22

from the anterior longitudinal ligament to just posterior to the nucleus pulposus

Question 23

What is the middle Denis spinal column?

Answer 23

from just posterior to the nucleus pulposus to the posterior longitudinal ligament

Question 24

What is the posterior Denis spinal column?

Answer 24

from the pedicles to the supraspinous ligaments

Question 25

What may cause a patient’s acute right back pain and sciatica?

Answer 25

a lumbar disc protrusion

Question 26

Which nerve root does lumbar disc prolapse intrude upon at the level of L4/L5?

Answer 26

the nerve root which exits at the L5 vertebra because it passes down across the atypical intervertebral disc while the nerve root which exits at the L4 vertebra passes above this area

Question 27

What is Cauda Equina Syndrome?

Answer 27

disruption of the annulus fibrosus either leads to to extrusion of the nucleus which impinges upon a spinal nerve or extrusion of the nucleus which compresses nerve roots within the narrowed spinal canal (CES)

Question 28

What are the symptoms of CES?

Answer 28

loss of sensation, pain, weakness, bilateral symptoms and “saddle” anaesthesia