Lecture 6: MSK Imaging 1 - Imaging Principles and Back Flashcards
What are important features of vertebrae?
vertebral body, pedicles, transverse processes, inferior / superior articular processes, laminae, spinous process
What are the characteristics of a typical cervical vertebra?
small anterior vertebral body, transverse processes which possess transverse foramina and uncinate processes
Which cervical vertebrae are atypical?
C1 and C2
What are the characteristics of C1?
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
What are the characteristics of C2?
C2 has an odontoid process which protrudes above and acts as the vertebral body of C1
Which ligaments extend from the upper part of the odontoid process to the inner part of the foramen magnum?
the alar ligaments
Which ligament extends superiorly and inferiorly from the odontoid process?
the longitudinal band of the cruciform ligament
What is the role of the much larger transverse band of the cruciform ligament?
has a higher importance in holding the dens stable
What are the five major densities on X-ray and CT?
metal: white
bone: light grey
soft tissue: grey
fat: dark grey
air: black
What is the difference between T1 and T2 MRIs?
in T1 MRIs fluid is dark, whereas in T2 MRIs fluid is bright
What are the three major views of a plain radiograph?
anterior-posterior (AP)
lateral
peg / odontoid view
What is the supplementary view of a plain radiograph?
oblique
How is a normal cervical spine identified using AP and lateral views?
checking the structure and alignment of anterior, posterior and lateral projections
How is a normal cervical spine identified using a peg view?
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
How is a normal cervical spine identified using an oblique view?
checking for normal neural foramina
What causes Hangman’s fracture?
bilateral pars or pedicle fracture
How can a Jefferson fracture be identified?
C1 burst fracture
very large discrepancy in how far the lateral masses are from the dens
How can an anterior longitudinal ligament disruption be identified?
the dark line of the anterior longitudinal ligament disappears at level C6-C7 in this case and reappears further down
What causes disruption of the anterior longitudinal ligament?
hyperextension
What are important things to look out for when diagnosing an injury to the spine?
normal alignment of vertebral bodies
even spacing between the pedicles
normal alignment of spinous processes
What are the Denis spinal columns and how can they be used to determine the severity of a spinal fracture?
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
What is the anterior Denis spinal column?
from the anterior longitudinal ligament to just posterior to the nucleus pulposus
What is the middle Denis spinal column?
from just posterior to the nucleus pulposus to the posterior longitudinal ligament
What is the posterior Denis spinal column?
from the pedicles to the supraspinous ligaments
What may cause a patient’s acute right back pain and sciatica?
a lumbar disc protrusion
Which nerve root does lumbar disc prolapse intrude upon at the level of L4/L5?
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
What is Cauda Equina Syndrome?
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)
What are the symptoms of CES?
loss of sensation, pain, weakness, bilateral symptoms and “saddle” anaesthesia
